Second Life does great too on the Mini, only getting a little slow at the highest settings with atmospheric shading, water reflections and shadows on all objects. Set up a RAM disk of 2Gb though, as the mobile hard drive is too slow for all the texture swapping.
I have the 2.5 mini with 8gb ram and a Vertex4 SSD. Mainly play League of Legends, Starcraft, Portal 2, all run very well in 1080p with mid-high settings. Very impressed at how it handles with 256mb vram.
League of Legends is free to play, so go ahead and give it a try! I also believe WoW is now free until lvl 20 if that would help as well.