Well the FX will be less money but the i7 will have a slight performance advantage.
Ram, get all you can get! You can get 16GB for under 100 USD so that is not a problem if you are looking at either i7 or Zambezi FX based systems. I prefer nVidia cards myself. GTS or GTX series are good choices. Just make sure they are DX11 and OpenGL 4.0 approved (for future apps). A good 22" LCD will be pretty cheap as well. Maybe look at a 24" if you can get a good deal. Motherboard, if you get an AMD cpu look at an ASUS motherboard. If you go i7 then stay with intel boards imho. 1 TB hard drive is a must. I still like having a DVD-RW drive myself.