hey there...go to a site like newegg.com or tigerdirect.com (newegg is my personal favorite) and they can narrow down your search criterea to exaclty wut u want. dont worry about big names like gigabyte or intel...just pick out the cheapest board that fits ur specs...o...and dont pick a board with mail-in rebates...you'll regret it later
If you recall he asked you to pick one out for him. Biggy, this mobo has what you want with a good, stable chipset. It isnt in stock but it fits you budget and has a ot fot hings for the money. I have had good aqauntinces witht his company too. http://www.newegg.com/app/ViewProductDesc.asp?description=13-135-177&depa=1
It's exactly the one I got. It's hard to find the mobo of your specs from Newegg without going over the $100 mark, unless you go with a cheap manufactured motherboard. Gigabyte is proven reliable with me so I am recommending this to you. It's about $20 over your budget, but it's a good board that supports your Athlon 64 and has PCI-e interface.