Ram:
MB: Gigabyte H77M-D3H
PSU: Corsair Cx 430/500 (I think it's enough to power this system)
Case: Zalman Z11
DVD R/w: Asus DVD writer
Storage: Corsair Force series 60Gb SSD+500Gb HD
Monitor: Samsung 21.5 Inc (1920x1080)
I would say the i3 and the 7850 for now and if you need more power in the future you can sell off the i3, grab a i5 or i7 and either crossfire the 7850 or sell it and get something better
PS: I am planning my own build now and have found that if you want to play BF3 (64 multi) then a i5 is oddles better than a i3