Below is a preliminary listing of the items that you can obtain without having to step foot into a raid instance. They are grouped by armour type and in descending order of item level but, as usual, this is not meant to be a BIS list. Such lists are extremely difficult to formulate because so much depends on your raid size, healing assignment and current level of haste with respect to break points.
I have excluded PvP obtained gear and crafted items with Resilience. While they may fill in temporarily, there is always a better item that can be found elsewhere.
By request, I've included items oriented more towards Balance.
That said, some rough pointers are:
1. Higher item level is generally better because Int is by far the best attribute and it increases with more powerful gear
2. Helms with a meta socket are better than those without it. Obtaining a meta socket should be a priority.
3. Keep haste slightly above break points. If you drop below then your HPCT and HPM will decrease.
4. Mastery is generally more attractive if you heal 10 player content or are assigned to tank heals.
It is worthwhile to note that greens are comparable with (or even surpass) ilvl 277 by the time you get to Twilight Highlands. Unlike previous expansions, it is extremely unlikely that you will want to be wearing any of your WotLK gear when you begin raiding and doing so will probably put you at a large disadvantage.
Helm
[Camouflage Bio-Optic Killshades] obtained from Engineering. With appropriate Cogwheels, this item is comparable to Tier 11 raid items.
[Cluster of Stars] obtained by spending 2,200 Justice Points in your capital city. This is the only other pre-raid helm with haste.
[Cowl of Rebellion] drops from Vanessa Van Cleef in Deadmines (H)
[Willowy Crown] drops from Ascendant Lord Obsidius in Blackrock Caverns (H). No spirit so it may not be useful.
[Helm of Reorigination] is a reward from the quest Doing It The Hard Way from Blackrock Caverns
Amulet
[Yellow Smoke Pendant] &
[Lightning Flash Pendant] are obtained from Dragonmaw: Exalted & Wildhammer: Exalted respectively
[Acanthia's Lost Pendant] is a zone drop in Blackrock Caverns (H)
[Amulet of Tender Breath] obtained from Altairus in the Vortex Pinnacle (H)
[Celadon Pendant] obtained by spending 1,250 Justice Points in your capital city
[Quicksilver Amulet] obtained from Karsh Steelbender in Blackrock Caverns
[Winking Eye of Love] most likely obtained from Valentine's Day event in SFK
[Pendant of Elemental Balance] obtained from Earthen Ring: Honoured
Itemised more for Balance:
[Charm of the Muse] is a zone drop BOE from Halls of Origination (H). There is also a normal mode version
[Charm of the Muse]
[Tauntka's Necklace] obtained from High Prophet Barim in Lost City of Tol'vir. There is also a normal mode version
[Tauntka's Necklace]
[Pendant of the Keep] obtained from Baron Silverlaine in Shadowfang Keep (H)
[Pipefish Cord] obtained from Neptulon's Cache in Throne of the Tides (H). This might be quite good for Resto
[String of Beaded Bubbles] obtained by spending 1,250 Justice Points in your capital city
Shoulders
[Gladiator's Kodohide Spaulders] are currently showing as having no resilience. If this bug goes live, they are an excellent candidate.
[Mantle of Bestilled Winds] obtained from Altairus in Vortex Pinnacle (H)
[Mantle of Soft Shadows] obtained from Anraphet in Halls of Origination (H). There is a normal mode version
[Mantle of Soft Shadows]
[Somber Shawl] obtained by spending 1,650 Justice Points in your capital city
[Spaulders of the Endless Plains] &
[Mantle of Wild Feathers] are obtained when Honoured with Dragonmaw or Wildhammer repspectively
Back
[Azureborne Cloak] obtained from Drahga Shadowburner in Grim Batol (H). There is a normal mode version
[Azureborne Cloak]
[Solar Wind Cloak] obtained from Rajh in Halls of Origination (H). There is a normal mode version
[Solar Wind Cloak]
[Springvale's Cloak] obtained from Commander Springvale in Shadowfang Keep (H)
[Cloak of the Dryads] obtained from Guardians of Hyjal: Honoured
Itemised more for Balance:
[Periwinkle Cloak] obtained from Lady Naz'jar in Throne of the Tides (H).
[Shadow of Perfect Bliss] obtained from Asaad in Vortex Pinnacle (H).
Chest
[Chestguard of Nature's Fury] is BOE & craftable by Leatherworkers. It's not perfectly itemised but is the only pre-raid epic chest piece available right now
[Cursed Skardyn Vest] obtained from General Umbriss in Grim Batol (H)
[Robes of Forgetfulness] obtained by spending 2,200 Justice Points in your capital city. This is the only pre-raid high end blue with haste & spirit
[Vest of the Curious Visitor] obtained from Glubtok in Deadmines (H) if you happen to prefer crit to spirit
[Robes of the Loving Ursine] drops from Defias Overseer in Deadmins (H) but seems to be 21 ilvls too low. This may be fixed.
[Wrap of the Fallen City] obtained from quest The Fall of Neferset City in Uldum
Wrist
[Manacles of the Sleeping Beast] are a zone drop from Blackwing Descent. You may be able to trade with another guild for them early on
[Armbands of Change] obtained from Corla, Herald of Twilight in Blackrock Descent. These are the only ilvl 346 blue wrist with haste
[Oasis Bracers] are a BOP zone drop in Lost City of Tol'vir (H). There is a normal mode version
[Oasis Bracers]
Gloves
[Aessina-Blessed Gloves] obtained from Guardians of Hyjal: Revered
[Blessed Hands of Elune] obtained by spending 1,650 Justice Points in your capital city
[Deep Delving Gloves] obtained from Slabhide in Stonecore (H). There is a normal mode version
[Deep Delving Gloves]
[Gloves of the Uplifted Cup] obtained from Baron Silverlaine in Shadowfang Keep (H)
[Gloves of Baleflame] obtained from the quest Closing a Dark Chapter in Grim Batol (N)
Legs
[Leggings of Consuming Flames] are a zone drop and BOP. Pray you get lucky.
[Blazewing's Furious Kilt] is a BOE with unknown drop location. However, there is a rare phoenix Blazewing which may drop it. Check the AH
[Leggings of Clutching Roots] obtained via Earthen Ring: Revered
[Leggings of Late Blooms] obtained by spending 2,200 Justice Points in your capital city. This are the only ilvl 346 blue leggings with haste
[Leggings of the Path] obtained from Siamat in the Lost City of Tol'vir (H). There is a normal mode version
[Leggings of the Path]
Waist
[Lightning Lash] is BOE & craftable by Leatherworkers
[Withered Dream Belt] &
[Belt of the Untamed] obtained via Dragonmaw: Exalted and Wildhammer: Exalted
[Thatch Eave Vines] obtained by spending 1,650 Justice Points at your capital city
[Underworld Cord] obtained from Earthrager Ptah in Halls of Origination. There is a normal mode version
[Underworld Cord]
Boots
[Awakening Footfalls] obtained from Temple Guardian Anhuur in Halls of Origination (H). There is a normal mode version
[Awakening Footfalls]
[Decapod Slippers] obtained from Mindbender Ghur'sha in Throne of the Tides (H)
[Tarvus's Poison-Scarred Boots] obtained from the rare spawn Tarvus the Vile in the southern most cave in Obsidian Forest in Twilight Highlands
[Vision-Tainted Treads] &
[Treads of Revelation] are obtained from the quests Traitor's Bait (Orgrimmar) and A Villain Unmasked (Stormwind) respectively
Ring
[Ring of the Boy Emperor] obtained from Archaeology if you get obscenely lucky with Tol'vir fragments
[Band of Life Energy] obtained from Ammunae in Halls of Origination (H). There is a normal mode version
[Band of Life Energy]
[Diamant's Ring of Temperance] obtained via Therazane: Revered
[Kibble] obtained from Beauty in Blackrock Caverns (H). There is a normal mode version
[Kibble]
[Ring of Frozen Rain] obtained from Asaad in the Vortex Pinnacle (H). There is a normal mode version
[Ring of Frozen Rain]
[Ring of the Great Whale] is a BOE drop from Throne of the Tides
[Veneficial Band] obtained from Augh in Lost City of Tol'vir
Itemised more for Balance:
[Anthia's Ring] obtained from Mindbender Ghur'sha in Throne of the Tides (H)
[Band of Rays] obtained from Rajh in Halls of Origination (H). There is a normal mode version
[Band of Rays]
[Spirit Creeper Ring] obtained from General Husam in Lost City of Tol'vir (H). There is a normal mode version
[Spirit Creeper Ring]
[Lavishly Jeweled Ring] obtained from Admiral Ripsnarl in Shadowfang Keep (H)
[Rose Quartz Band] obtained from Slabhide in Stonecore (H)
[Abandoned Dark Iron Ring] zone drop BOE in Grim Batol (H). There is a normal mode version
[Abandoned Dark Iron Ring]
Weapons
Note that there is no specific Enchant Staff type spell in Cataclysm, all weapons can have the same enchants.
Note also that Enchant Off-Hand is being changed to +40 (down from +100) Int in patch 4.0.6. This will bring the overall Int of MH/OH in line with Staves and the decision between them will rest more on loot luck and differences in secondary stats.
Note also that a ilvl 346 Off-Hand is buyable with Justice Points or craftable and 346 1H Maces are craftable. That raises the bar on raid entry level weapons to pretty much 346 blue.
1H Weapons
[Elementium Hammer] crafted by Blacksmithing
[Scepter of Power] obtained from Setesh in Halls of Origination (H). There is a normal mode version
[Scepter of Power]
[Shimmering Morningstar] &
[Shimmering Morningstar] obtained from Hellscream's Reach: Revered & Baradin's Wardens: Revered respectively
[Torturer's Mercy] obtained from Rom'ogg Bonecrusher in Blackrock Caverns (H)
[Gurgthock's Garish Gorebat] obtained from the Crucible of Carnage event
Itemised more for Balance:
[Modgud's Blade] obtained from General Umbriss in Grim Batol (H). There is a normal mode version
[Modgud's Blade]
[Elementium Spellblade] crafted by Blacksmithing
[Biting Wind] obtained from Grand Vizier Ertan in Vortex Pinnacle
[Beak of Julak-Doom] obtained from Julak-Doom, outdoor boss
2H Weapons
There are very limited choices for Resto
[Staff of Ammunae] obtained from Archaeology if you get obscenely lucky with Tol'vir fragments
[Staff of Isolation] obtained from Lord Godfrey in Shadowfang Keep (H)
[Soul Releaser] obtained from Earthrager Ptah in Halls of Origination (H)
Itemised more for Balance:
[Staff of Sorcerer-Thane Thaurissan] obtained from Archaeology if you get obscenely lucky with Dwarf fragments
[Staff of Siphoned Essences] obtained from Erudax in Grim Batol (H). There is a normal mode version
[Staff of Siphoned Essences]
[Emberstone Staff] obtained from Foe Reaper 5000 in Deadmines (H)
[Cerith Spire Staff] obtained from Commander Ulthok in Throne of the Tides
[Insidious Staff] &
[Insidious Staff] obtained from Hellscream's Reach: Revered & Baradin's Wardens: Revered respectively
Off Hands
[Apple-Bent Bough] obtained by spending 950 Justice Points in your capital city
[Prophet's Scepter] obtained from High Priestess Azil in Stonecore (H)
[Divine Companion] cratfable by Inscription
[Bioluminescent Lamp] obtained from Neptulon's Cache in Throne of the Tides (H)
Itemised more for Balance:
[Hermit's Lamp] obtained by spending 950 Justice Points in your capital city
[Dungeoneering Guide] craftable by Inscription
[Beauty's Favorite Bone] obtained from Beauty in Blackrock Caverns (H)
Relics
[Tattooed Eyeball] craftable by Inscription. Not well itemised for Resto however
[Book of Dark Prophecies] obtained from High Priestess Azil in Stonecore (H)
[Book of the Well Sung Song] obtained from Vanessa Van Cleef in Deadmines (H)
[Captured Lightning] obtained from Asaad in Vortex Pinnacle (H)