My 8800gt just died and im holding out for the kelper series to release but for the mean time im willing to spend 100$ on a new graphics card any suggestions?
I don't know what your using your PC for. The 6770 can run most games at 1900x1080 if you don't turn everything to max in the settings. The 6670 will be good for light gaming at 1600x900. The nvidia 670 will be out on May the 10th. But the 660(ti) isn't coming out till Q3 2012. The 6770 would be my pick if you play a lot of games and don't mind lower detail for a few months.
Overall, the HD 6770 has about 30% better performance than the HD 6670. At just $35 more (a little more than $1 per 1%), the HD 6770 is a better choice since it is still within your budget.