Dont get an Ultra PSU, they arent that good, try to get one from antec, PC Power & Cooling, Seasonic, or OCZ. The corsair 450VX should be plenty
Where are you buying from ? I would really suggest upgrading from that resolution, a 4670 can handle it rather well. A 4670 will save you quite a bit and will give you playable frame rates at that resolution on crysis on high. Also dont buy a copy of XP, get a copy of vista with the upgrade coupon, its definitely worth it.
If you do decide to get a monitor with it then my graphics suggestion would change to reflect the resolution on that monitor.