RE: DC racing games: I remember spending too much time with Rush 2049 and MSR and Tokyo Xtreme Racer (1&2).
Rush 2049 has some awesome arcadey tracks - driving up buildings and loops and stuff...
MSR is tough but rewarding - it is the precursor to Project Gotham on the Xbox....
Tokyo Xtreme Racer was fun one on one street racing.
Sega Rally was also an arcade style treat...
Sega GT - I didn't enjoy.