No idea about your budget, just suggest some with good value for money...
Athlon IIx 4 630/ Phenom II x4 955
ASRock M3A770DE/ ASRock M3A785GMH/128M/ MSI 790X-G45
core i3 530 + GIGABYTE GA-H55M-UD2H
Core i5 750 + ASRock P55 Pro/ MSI P55-GD65
Core i7 930 + ASRock X58 Extreme/ GIGABYTE GA-X58A-UD3R