As Trokck already (re)said. The basic flat math says hit has a 40% edge in the item budget. If you factor in other things that edge is diminished. Lower than a certain percentage of crit I do think it equals or surpasses that 40% but that is subjective and depends greatly on build.
However, even these numbers are misleading. The fact of the matter is you also have to take how item budget allocation weighs into all of this. Items that have one stat stacked on them are almost always inferior to their counterparts with stats spread out. A good example is.
http://www.wowhead.com/?item=32266 - Ring of Deceitful Intent
+21 Agility
+42 Stamina
Equip: Improves hit rating by 19.
Equip: Increases attack power by 58.
For the same item budget you could create an item:
+21 Agility
+32 Stamina
Equip: Improves hit rating by 21
Equip: Improves critical strike rating by 21
Equip: Increases attack power by 42
If you took this same approach to all of your items (perhaps weighted a tad less towards hit so in a full set you would sit at the cap) you would do vastly more DPS than trying to stack stats on individual items.
So yeah, go with Kaylaan's Signet and Slayer's Mark of Redemption. I wore that set for a long time and only recently swapped in the Kara rep ring because I was dangerously low on stamina (7k buffed).
And yes, I got tired of my mage and came back to my hunter. I gripe and bitch but this stupid class grabbed me back in beta and hasn't let go. Mage never made it past 53 =(