Picked up my dreamcast bundle for $75 last winter... Really glad i did, lots of great games.
Heck, you can get most of the best games for $10 right now...
Short Favorites List:
-Jet Grind Radio (sorta like a car chase-game on skates)
-Tony Hawk2 (fun trick skating game)
-Soul Calibur (sweet fighting game)
-Crazy Taxi (fun game, cool music)
-Shenmue (for people who like HUGE RPG type games)
-PSO (careful though the online play has been hacked to death, offline still fun diablo type game)
Well, these are the ones i play the most...
I still unplug the PS2, to play the dreamcast every other week.
OHHH, try the dreamcast with the VGA adapter-($10-15), on a computer monitor the detail is sweet.