Well I don't know too much about specific track names or anything like that but...

Seed- opening 1 and opening 2 are damn good tracks. I also like the high-paced, battle music that is often background to MS deployments and mothership tactical manuevers and strikes.

G-Gundam - This show had music? I really can't recall...

Wing- ok, I also really liked Rhythm Emotion & White Reflection wasn't too bad either. Some of the battle music were phat Bullet Rain & (I think its called Burn- the one playing in the big duel in the last episode-) but I really like the sort of spacy, eerie music that they play in the background when describing the political situation or whatnot. It's sorta makes you feel complacent and reall fits the whole outer space feeling, I thought.

GSD - again pretty good battle music, the comedy theme is retarded. Opening 1 is still my favorite.

Oh, and if anyone ever played the Gundam Wing: Endless Duel for SNES game, the track for fighting against Heavyarms is incredible!!! I suggest everyone download it, as it is a pretty cool techno track and really perfect for a video game arcade fight like that. It is MIDI-ish quality but still cool