QUOTE(metaldevil @ Mar 29 2006, 08:17 AM)

You don't need anyone here to tell you what you're going to like. Decide for yourself. Download the trials, and purchase the one you like best.

yeah definitely, I myself have downloaded just about every Trial Live game avaible... If you decide to buy it just unlocks it, you wont actually have to download it again.
IMO the 5 best Live Arcade games (in no particular order)
-Hexic
-Geometry Wars
-Marble Blast Ultra
-Bankshot Billiards 2
-Feeding Frenzy
I probably wouldn't have bought Bankshot Billiards but like you I got it free with the Live Starter kit (actually my GF bought the kit for herself so I got the game by proxy

) I'm glad she did because it's easily one of my favorite games and really great to play if you have 1 or 2 friends (particularly non-gamers) who want to play a quick and easy pickup game.
If you're looking for Gameplay almost IDENTICAL to geometry wars check out, Crystal Quest, Mutant Storm Reloaded, Smash TV, and Robotron. All of those games have the same style gameplay as geometry wars, I've heard lots of good things about mutant storm and Crystal Quest is a good distraction (but not really worth 800MP if you ask me) Smash TV I really like (but more more nostalgia reasons) and both Smash TV and Robotron are based off of their arcade classics. Also Robotron and Smash TV offer multiplayer, which is something the other games don't have.