I suppose my view might seem biased, but really it's not - apart from Crysis in some reviews and a few TWIMTBP games, the HD 4770 beats the 9800GT, and in a few games the HD 4770 performs right alongside the 9800GTX+.
http://www.pcgameshardware.com/aid,682726/Review-Ati-RadeonHD-4770-vs-HD-4850-und-Geforce-9800-GT/Reviews/
The HD 4770 is better out of those two. But, why not get the HD 4850 for ~ $100 off newegg?