I would go for the propus 620 quad core amd for $99 at newegg. Check out their combo deals; they had at least one for less than $200. For the 785 chipset boards, the onboard graphics are pretty good for a non gamer. You can try them first and add a card later if needed. The operating system and ddr3 will be your biggest choices. Frys had xp home for $59.99 a couple of days ago before the windows 7 launch. A pricewatch vender has 64 bit xp for $47, which is a pretty good deal. If you finish pricing out all your components and your total is over $650 consider a system by hp or dell. Frys has a quad core 910 amd system with 8 gb of ddr3 and windows 7 for $699 in stores only.
I definitely suggest windows 7 over XP or Vista, i have been running Win 7 Pro 64 bit for a couple months now and it is actually very nice, and runs extremely well, XP 64 was the first venture into 64 bit OS's and is known to have had some issues.
You know you can order things from newegg and pay with a personal check rather than use a credit card if you live in a country that you can order items from newegg.
Last year I didn't have a credit card so I ordered things by a check.It took a few days longer though.