PC Hardware → Video Card Choice w/ Limited Hardware

Hey all - I've read some great posts on this subject, but wanted someone's seasoned / experienced advice on these 2 particular choices.

I'm running an Intel Core 2, E8400 @ 3 GHz, 2 gig RAM w/ Win 7 - 32 bit. Yea, it's old, but still runs great for my needs, and a system upgrade is not in the near future, so....
For an upgrade from my current (OK, NOT so current - LOL) GeForce 8600GT, I'm looking at:

1. A GeForce GTX560 w/ 1 gig GDDR5

or

2. A GeForce GTX 560ti w/ 1 gig GDDR5

The ti version is approx. $60 more - is it worth the difference with this processor? These really are the 2 choices I have in mind, and definitely going Nvidia. I've been told a 570 is simply overkill for this processor; some have suggested the ti is as well, but I'd spend the extra $60 if it will actually make a difference.

Thanks for helping me make the right choice!

GTX 660, or GTX 660 ti was rumors to be $250. Some time next month.. But again rumos.

What is the game that is driving the upgrade?

Also, unless you are absolutely sure that your power supply won't have any issues with this upgrade it would be best to tell us the brand and model of your supply or brand model of machine if it is a big name box.

The 560 you are looking at is the 384 core version. There is also a 448 core version. I would say, in general, that if the $60 is important to you that you not spend the extra for the ti. The 584 core version might be 15% faster, on average, than the standard 560. The 448 core is moving that into more significant territory, maybe 1/3.
If you are willing to tell us the game that is driving the upgrade then I will rethink my answer, depending on the needs of the game.
If you just want something faster but don't have a specific reason then I would wait until you actually need the upgrade and then determine what you need at that point.

I have a 4 year old PC I put together myself with quad core 2.4ghz Q6600 overclocked to 3ghz and a 9800GT. I am able to play any new game out thus far at 1680x1050 with at least medium graphic setting and still maintain 30+ FPS. This is probably the longest I have gone without building a new system since I just dont feel I need to yet.

The day I try playing a new game and cannot get good performance with at least medium graphic settings is the day I upgrade the video card.