Well, it really depends on what kind of player you are.
I don't play RPGs that much. The Dreamcast had a shitload of arcade perfect ports and that was more than enough for me.
It was hard to keep up with the japanese releases at the time. All the fighting games (3rd Strike, SFZ3 Upper, SSFIIX, Jojo, Vampire Chronicles, Soulcalibur, Rival Schools 2, Dead or Alive 2, Guilty Gear X, SNK vs Capcom 2, Marvel vs. Capcom 2, etc) the shitload of shmups (Zero Gunner 2, Ikaruga, Border Down, Mard Matrix, Gigawing, Psyvariar 2, etc), the Naomi ports (Crazy Taxi, House of the Dead 2, Virtua Tennis, Power Stone, F355 etc) and yeah, I even enjoyed some of the SNK "enhanced ports" (KOF 98 Dream Match) I still have the DC=>NGPC cable).
The Dreamcast was awesome imo. I still have one in my cab all set up as the poor man's Naomi.