Is there maybe someone that consistently games on his iMac - as is to say often in a Bootcamp partition?

I'm an Apple user for general computing, but I like gaming A LOT.
I don't have that much time but I'm really an enthusiast of videogames as a medium and tend to buy and try them whenever I can.

I was considering to build a new gaming PC and hook it to my 23'' LG 120 Hz monitor but still can't pull the trigger: that machine would be used only for gaming and I already have 360, PS3... and Wii. /ashamed
So I'm thinking of selling that monitor and buying a new 27'' iMac with ATi 6970 2 gb, using it as main machine (now I have a late 2008 Macbook Pro) and gaming on it on a Bootcamp partition with my (more or less) trusty W7 64 bit.

I understand 6970 mobile is more or less equivalent to a desktop 460, but obviously the native resolution of the iMac makes it nearly mandative to play in 1080p... any experiences and opinions?
Is it very blurry at that resolution?
How's the gpu faring?

Thanks a lot for your valued help in my decision making! ;-)