I really liked 2...It was odd, but once I played a couple of hours in, the story seemed to take off and I was actually interested in what was going to happen to the cast (maybe not the world so much). I remember I really liked Kanon and the fights with her were some classic good RPG fights. It did drag on, but it was rewarding (although the one translation puzzle in the final dungeon had me reaching for Gamefaqs more than once...It was awful). I didn't care so much for Code F, but I'll buy a remake of 2 without hesitation. It had a lot of intangibles working for it that a lot of RPG's seemed to lack at the time (and now, for that matter).
Mixed responses to the remainder of the games...I finished 1, but barely. I'm somewhere near the end of WA3, but the game lost all sense of being engaging somewhere around 10 hours in (if that). 4 has potential, but it's on the backlog for possibly eternity right now. Those Klonoa sections should be used in their own seperate game.
Suffice to say, I want to see 5, but not with the same level of anticipation for VP2 or Suikoden 5 yet.
My only complaint with 3's OST is the dungeon tracks are lacking compared to 2's and there aren't nearly as many. Other than that, it's a strong favorite.