I finally upgraded too
but i ran into some problems, i bought Asus 560 ti dc top factory clocked at 900 core.
At first the performance was good, then it almost cut in half, to even lower then my gtx 260
I was really puzzled, according to msi afterburner the card was running at its optimal clock speeds. So i figured maybe its my old 600w psu that is to blame even though its enough as its run the gtx 260 just fine. Just in case i bought a new 800w modular single rail psu the following day but still no dice.
Today i went down to the store and had the card replaced and presto now its awesome