I have and highly recommend the following board.
http://www.tigerdirect.com/applicati...?Sku=A455-2863
It's about as cheap as a full featured board can get and still have a low price. I realize it may be a little sort on connections only 2 SATA and 1 IDE. It has 4 built in USB ports and 3 USB headers for a total of 10 USB ports. It supports AM3 chips with a BIOS update. I've had the system for abotu a month now and it's been great on Windows 7 with AMD Athlon X2 5000+ CPU and 4GBs of RAM.
From Tigerdirect.com "The Asus M2N68-AM SE2 motherboard features the NVIDIA Geforce7025/nForce 630a integrated chipset, which combine multiple graphics solutions and highlight NVIDIA PureVideo technology that deliver the outstanding graphics performance. It supports the latest AMD socket AM2+ processors including the latest Phenom X4 Quad-Core processor. Memory compatibility includes up to 4GB of Dual-Channel DDR2 memory at speeds of up to 1066MHz."