Here's a couple of options for you:
Or, if you opt for an i3 CPU instead [which is still good for gaming] you can get a better graphics card:
or an AMD 6950 for the same price here.
Do you have a 64bit OS for the 8GB of RAM?
Some comparisons for you:
i3 vs i5
6950 vs 560Ti 448
6950 vs 6850
Hope that helps! Couple of things to note:
There are a few cases at that price range if you'd prefer a difference one, such as the Bitfenix Merc or CoolerMaster Elite 430
Also Ivy Bridge [Intel's new CPUs] are out soon, so it might be worth waiting for that if you wanted to.