If you can afford it, the last one would be very good, with the HD5850, although that may be a little overkill for your current resolution. Find a PSU that has full range active PFC (no little voltage switch) and 80+ certification. Antec, Corsair, PC Power & Cooling, Seasonic, and Enermax are among the better brands. The older Coolermaster PSUs (with the voltage switch) definitely are not. Five hundred watts would be a good size.
Edit: Between your last two GPU choices (GTS260 or HD5770) I would choose the HD5770. You might get that nice discount, you'll have DX11, and you'll use less power.