If you could stretch the budget slightly and get a 570gtx that would be great :)
The 560ti is a great card, i have one :D, but ultimately its stil a mid range card (in fact i have that exact card! lol). Do you have a preference for Nvidia? Because you could also go for the 6950 1gb which is priced in the same range as the gtx560ti. The 6950 will generally outperform the 560ti.
Personally im more of an nvidia guy so il stick with the 560ti if you cant get the 570.