I would agree that the Wii Virtual Console has a great list of older games.
But I will go a long to say that I think that LIVE arcade has a great list too. It almost seems that Xbox 360 gets a revamped version of older games most of the time.
XBOX LIVE: macr0planet
PSN: MacroPlanet_DSGN
Steam: MacroPlanet
Modern Warfare 2 - Uncharted 2 - Assassin's Creed 2 - Mass Effect 2 - Alan Wake - Forza 3 - Splinter Cell: Conviction - God of War 3