Hello. Another noob here. Have also had a DC since 2001. Got it largely for the 2D fighters available for it at that time. I don't play those much anymore though. It's mostly racers (arcade style preferably) and shmups for me now; which probably goes without saying, looking at my list.
Anyway...
US gamesBangai-O
Canon Spike
Capcom vs SNK
CART: Flag to Flag
Crazy Taxi
Daytona USA
Dead or Alive 2
Ducati World Racing Challenge
F355 Challenge
Fatal Fury: MotW
Giga Wing
Giga Wing 2
Gunbird 2
House of the Dead 2
Illbleed
King of Fighters: Dream Match 1999
King of Fighters Evolution
Last Blade 2
Magforce Racing
Mars Matrix
Marvel vs Capcom: Clash of Super Heroes
Marvel vs Capcom 2
Metropolis Street Racer
Resident Evil: Code Veronica
San Francisco Rush 2049
Sega GT
Sega Rally 2
Sega Smash Pack v1
Soul Calibur
Speed Devils
Star Wars: ep.1 Racer
Street Fighter 3: 2nd Impact
Street Fighter 3: 3rd Strike
Street Fighter Alpha 3
Test Drive -Le Mans 24hrs
Test Drive -V Rally
Tokyo Xtreme Racer 2
Tomb Raider: Last Revelation
JapaneseBorder Down
Capcom vs SNK 2
Ikaruga
Karous
King of Fighters 2000
King of Fighters 2001
King of Fighters 2002
Monaco GP 2
Psyvariar 2
Shikigami no Shiro 2
Trizeal
Under Defeat
UnofficialFast Striker
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As for accessories:
VGA box, Light Gun, Keyboard, a bunch of VMUs, and a couple (crap) 3rd party joysticks... That's about it.