Graphic card upgrade

Hi guys!

I want to upgrade my graphic card and I'm in a bit of a struggle. I have a decent build that dates back to the 2500k launch and upgraded a few times and I think it’s the next best thing to do. I play mostly solo RPG (ME serie, DA serie and the like) so I know I don’t need a top of the line card but my GTX 460 is starting to have a hard time keeping up. And it will only get worst.

The computer is mostly used for music production so I wish to keep it as quiet as possible while not under too much stress.

Right now, here’s what I have:
- Fractal Design Define R4;
- Corsair AX860 (overkill, I know, but it was a gift)
- Intel i5-2500k OC at 4,3 with the launch defect (yup!) but since I’m using only 2 drive, it doesn’t bother me much;
- Gigabyte P67A-UD3 as motherboard;
- 8 gigs of corsair vengeance 1600;
- 1 SDD and 1 HDD;
- Screen resolution is 1920x1080;
- And the GTX 460.

I know that with that motherboard I won’t get all the boost I could since it’s PCI 1,0. I’m going for a decent gain now but I’m hoping the graphic card will last through my CPU/Mobo that will probably be with the release of Haswell.

I know mostly of Nvidia so I was guessing GTX 660 ti or GTX 670. Money is not the main issue here: I prefer to buy the right product even it's a bit pricier.

So, any advice?

Tam