If you were a RPG and Fighting fan, you would already have a DC, no questions asked!
Capcom vs. SNK (best 2D fighter ever)
KOF Dream Match 99
Street Fighter Alpha 3
Street Fighter 3: 1,2,3
Virtua Fighter 3tb (best. game. ever.)
Fighting Vipers 2 (soon)
RPG\'s (may be the system FOR RPG\'s):
Skies of Arcadia (one of best I have ever played, almost as
good as Chrono Trigger, no joke)
Grandia 2 - about as long as Chrono Trigger, immense visuals
and great battle system. VERY recommended.
Shenmue - Not really an RPG, but best game ever.
Legend of the BladeMasters - Soon, online
Phantasy Star Online - 37 - 40 from Famitsu, what more can
I say? Oh yeah, Sonic Team! soon!
also, the Dreamcast is the system for racers:
Test Drive Le Mans
Tokyo Xtreme Racer 2
Metropolis Street Racer (soon, rated best racing game ever
by dailyradar UK!)
Test Drive V-Rally - great Rally game!
Daytona USA 2001 - the arcade raceer game. Their is no
other. Online too!
Get a DC now, then in 4 months. get a PS2. By then, PS2 will have great games and DC will still have many games coming out. Trust me.