Of the games I've bought for the system:
Halo: Fantastic
Amped: Pretty dull
DOA3: Not really a beat 'em up fan, but I reckon there are better in the genre
Rallisport Challenge: Disappointing
NBA2K2: Decent sports sim, though not much of an upgrade from NBA2K on the Dreamcast
JSRF: Not really my kind of game, but it has its fans
Morrowind: Massive RPG, dodgy combat and a few bugs, but a good game overall
Timesplitters 2: Early days, but I've found it quite dull so far