Question is.... 1GB or 2? I want to future proof the thing, but 2Gb gets $$ and I dont want to waste it if 1GB will do the job.
If you can manage it, get 2GB - that will definitely future-proof the system. Rage only looks "how it should(tm)" with 2GB of RAM for example, anything less and, in my opinion, it looks less impressive than most UE3 games - for example Bulletstorm, which is gorgeous

This is directly related to having enough RAM for the textures.
However, saying that - I have a GTX 470 with 1280MB, and it does a great job in most games. RO2 looks great on High, but sometimes suffers from FPS drops - mostly I'm 40+, so it's not too bad. Skyrim runs nicely too, on High rather than Very High settings.
One thing to concentrate on - if your CPU clock speed is less than the memory speed of the GPU, you won't get 100% from the GPU. For example my 470 RAM runs somewhere around the 3300 Mhz mark - but my CPU is currently clocked at 3Ghz (3000 Mhz) - so I am not getting full performance, but it's still impressive. I upgraded system RAM to 8GB recently, and now I know the new stuff is stable, I'll be OC'ing my CPU to 3.4 to make sure I get 100% from the 470
