well id rather buy a late 2010 or early 2011 mac... and put windows on it..
what does the macbook8,1 mean? the 8 and 1
I'd get at least a 2011 model, as it has sandy bridge and can take up to 16gb of cheap ram, which you'd want for windows and other vms, prior models only go up to 8.
The integrated intel HD3000 graphics on a 2011 13" should be faster than the graphics on the '09 C2D. The 09 also only only Sata 2 speeds, the 2011 has Sata 3; the 2009 cannot take full advantage of the latest SSD's.
It's a perfectly valid option to upgrade to 8gb of ram and a 750gb momentus xt ssd/7200 rpm HDD drive for $150-$200 and drive that puppy until the wheels fall off of it. My wife is still using my 2008 15" 2.4ghz C2D as a desktop replacement with 8 gigs of ram for doing ordinary browsing, etc, and she doesn't feel the least bit deprived.