You have another option too. By a notebook with ati/amd graphics.
I use a lenovo ideapad with integrated Radeon Mobile 4300 in combination
with Catalyst 10.9 and since one hour with 10.10.
It is the perfect choice for me.
My Nvidia GTS250 was the last Nvidia card for my Desktop, because
the drivers are very buggy. OC didn't work now for the last 3 revisions with the 260
series. With 256 drivers the plasma desktop works not good. When i change a movie
to full screen the picture stand for seconds and sometimes it crash the complete Xserver.
Questions to this problems wouldn't answered, see thread http://www.nvnews.net/vbulletin/showthread.php?t=156164