The PW games are pretty ace, but I'd have to go with either Retro Game Challenge, just because it's so damn cool or one of the Prof. Layton games. I dunno why, but they're so damn awesome. Final Fantasy Tactics was highly enjoyable though, as is the Fire Emblem game - despite there being a lot silly things about it.

It's silly, because I know I've played lotsa of games that I really liked, but they're not on my FC any more, and I can't remember them all too well.