PS3
Alot of Amazing Exclusives, (Uncharted 2, Killzone 2, Motorstorm ect
plus games that you and your GF can play together like LittleBigPlanet (one of the best games ever made)
even if your not intrested in Blu-ray movies, the games are also on Blu-ray which means amazing graphics and very finely tuned gameplay on Exclusives, plus you always have a blu-ray player for the future if you ever change your mind?
you can get online Free, built it wifi like the wii so no extra costs
games like FIFA and Assassins Creed 2, COD look great and play the same as any other system they are on
PS3 is the best value for money you can get and has a huge range of games that if your GF is not hardcore she can play aswell and love.
hope that was helpful