I'm not that big of a fan for Bejeweled and there are a bunch of SmashTV / Robotron clones but there's one game I absolutely love on XBox Live Arcade - Marble Blast Ultra.
Unfortunately I only rented the 360 so I'm not ready to me ordering the full version just yet but the demo comes with 7 or 8 levels in 3 difficulties and the sounds and graphics are awsome ;). Think Marble Madness in 3D with online competition and power-ups :).

Alright, enough plugging! Here's the track from the demo:
It's medium/up beat techno/trancy, very cool.

Marble Blast Ultra.mp3
http://members.shaw.ca/mres01/mp3/

- Mike