low price but good mini-ITX mobo for this project:
Newegg.com - ZOTAC NF630I-D-E LGA 775 NVIDIA GeForce 7100 Mini ITX Intel Motherboard - Intel Motherboards (http://www.newegg.com/Product/Product.aspx?Item=N82E16813500012)

REckon this would be great as a HTPC as well. I think I'll order 2.