Crandimanic's 12 hours have passed. My go. And I pick:
Street Fighter Alpha 3 (Playstation/Dreamcast, 1998)
With Super Street Fighter gone, I've picked my second favourite of the series. A massive roster to keep me busy, some really nice animation, a kick ass soundtrack and more than just an arcade mode to finish.
Love it.
Just to clarify, I'm picking the Dreamcast version.