Elle85: Puzzle Bots is also a very nice game, I get it on bigfish with a promo code and really enjoy it.
I get Puzzle Kingdoms at steam on last summer deal is Puzzle Quest: Challenge of the Warlords better? (sorry for noob question but i haven't play a lot of match 3 games)
Yeah, Puzzle Bots can be bought cheaper from BFG (when they issue their $4.99 coupons and so on, which is why I don't think the GG price is all that great).
Puzzle Quest is by the same folks as Puzzle Kingdoms I think, so it's basically the same thing. It is worth getting if you liked Puzzle Kingdoms, but be warned; the AI is not very friendly and some people will swear it cheats (such as me when playing the Japanese DS version which *was* bugged).
It's a shame GG aren't selling Fishdom discounted as that would be worth getting. By the spooky/frosty versions are a little too gimmicky for $9.99 (especially as they're available from BFG for as low as $6.99 usually.
Other games on GG I recommend are Delve Deeper and Dungeon Defenders (pre-order).