Which game is this 2D character sprite in a battle stance from?
She looks like she's from a Capcom fighting game, but the level of detail made me wonder which system. It looks too 2d for anything past the PSX/Saturn/Dreamcast era. Am I right?
She's Vice, capcomesque version. http://gaming.wikia.com/wiki/Vice
Adrian is right: It's Vice from King of Fighters (link)
King of Fighters was originally neogeo, though they've actually done a few crossovers with more conventional capcom games. It holds a special place in my heart for being the only fighting game series that I was actually really good at.
One of my fondest arcade memories was walking into an arcade that had just had a brand new KoF v Capcom machine delivered, and completely pwning all these kids who'd never even seen a neogeo. Played 5 games without losing a single round, got a buzz on my (at the time sexy and modern) pager, passed my game to some kid, and walked out a legend.