Help with CPU and GPU

I am building a PC for the first time and could use some advice. This is going to be a dual purpose PC (gaming and architecture design programs). The games I will be playing are FFXIV and FFXI. Other programs will be CAD, shader, and others i am not sure about yet.

1: CPU - Should I go with the 955 or the 1055T. I know games normally do not make use of the six cores but what about the design programs?

2: GPU - I am going to run an ASUS M4N98TD mother board for the two pci-e x16 slots, however i do not want to use sli mode. I want to run a gtx460 for gaming in one slot and a PNY VCQFX - 1800 as my workstation card. I have been told this should work. Any thoughts or advice here.

Other specs

Liquid cooling

4gb DDR3 1600 ADATA (upgrading to 8gb in January)

640 GB SATA - III (adding SSD as boot drive in January)

600w power supply Is this enough? From what I understand the workstation cards do not utilize as much power as gaming cards.

Is it worth is to upgrade my NIC card to a Killer Xeno Pro? Anybody had any experiences with these?

Thanks all