Please help me choose

Hi guys,

I know this must have been asked a zillion times but I am torn between multiple worlds and cant seem to make a decision.
I had set my mind on a 4870X2 but with every review I read and every chart I see, I'm having change of hearts. What triggered me first is the problems 4870X2s are having. I'm not very tech savvy and most importantly I dont have much time to solve these issues. So I would like a real plug n' play solution.

I know everybody would say get the 4870X2 since its a beast, but please consider these.

I dont want to go for 3DMark records.
I don't want to have the highest possible FPS.

What I want is a card that can serve me for about a year, and let me play most games at 1920-resolution in good detail.
I'm not sure but I don't know how much of a difference a gameplay would give between playing at 75FPS and 100FPS. Is it noticelbly different?

I considering Radeon 4870 or GTX260.

If someone really says GTX280 is a better choice too, I'll think about it too.

Please give me your advise. I need to buy this soon.

Other components of my rig 'will' be:
Asus P5Q Deluxe.
Q9550.
G.Skill 4GB (?)

Thanks a lot guys.