Oh man, Dreamcast is by far the greatest console of all time (IMO, of course).
-Sonic Adventure 1 and 2 (I prefer 2)
-Grandia 2 (favorite traditional RPG... ever.)
-Skies of Arcadia (can get frustrating, but once you get into it it's an amazing RPG)
-House of the Dead (buy a lightgun)
-Propeller Arena (Gonna have to search for this one *COUGHBITTORRENTCOUGH*)
-Half-Life (^^^^^^^^)
-Resident Evil: Code Veronica
-Crazy Taxi 1 and 2
-Floigan Brother (very short, but entertaining while it lasts)
-Super Magnetic Neo (quirky Japanese title)
-Samba de Amigo
-Jet Grind Radio (though I like JSRF better..)
-Headhunters (PAL only--Buy a DC-X to play it on NTSC)
There are more, but that's enough...
oh yeah..
SHENMUE!!(Naturally I'm referring to both games in the series
)