Take a look at this
Same intial cost as that 8600GT, but of course without the rebate. The 8600GT is a rather weak card, but then it's stronger than the 3650. Still, the Radeon 4670 is just so much faster. If you want to be really cheap though then you can always go with a 9500GT, which is just a die shrunk and faster clocked 8600GT. Still looks very weak compared to the Radeon 4670 though.