I think you'd be hard pressed to find a decent place where a green gem would actually be worthwhile. I suppose it's worthwhile if it gets you a +6 Stam or +6 Agi socket bonus, like
[Conqueror's Nightsong Handgrips], but even then it's pretty close to not being worth it, going by Nightcrowler's stat values. Going by Rawr, it's never worth it to use a green or yellow gem, once you significantly pass the survival caps, agi and agi/stam trumps defense/stam even with decent socket bonuses.