hi,
one of my roommates has a dreamcast and imho, it's not worth getting... yet. the two games he has are sonic adventure (not so great a game, despite being the "flagship" title for sega's new system launch) and namco's soulcalibur (the best fighting game EVER, bar none). soulcalibur kicks all kinds of petard and asks for more. it must be worshipped as the single greatest platform fighter (beating my previous favorite, tekken 3 on playstation), without question.
but other than that game, the library of extant games are mainly in the vein of sports or action titles with spiffy graphics. there are some rpgs coming out, but i'm holding out personally for the playstation 2. if you've got the dough to blow, go get a dreamcast and soulcalibur, however. it's cheaper than owning the arcade version and the sega version actually has more moves, characters, better graphics quality (!!!) and more play modes.
caveat emptor.
/willko.