There are many boards for about $80-125 USD with an nforce2 chipset. The nforce2 is actually 4 different versions with different limitations now. You have to be very careful when picking a board.
Dual channel DDR or Single channel DDR.
FSB max speed 333 or 400.
Support 333 or 400 mhz memory speed. (May all be 400 now.)
Do you want dual DDR? That raises the price.
Do you want 400 mhz FSB? That raises the price.
Then all the extras raise the price too - RAID, SATA, FIREWIRE, etc.
Give us some more details.
And don't forget shipping cost $5-20 depending on the site.
Actually thinking about it. Crack openthe piggy back and get a top end board for $120. If you don't have a feature in 6 months you will have to pay $50 to get an add on card or a whole new MB for $100.
I should have mentioned that your current CPU will run in this setup, and a decent videocard say a ATI 9600(nonpro) for about$100 wouldn't be a bad way to go for cheap too. As far as power supply, I wouldn't go below 300 wt. It's all relative to what you want. I personally don't think I need all the latest and greatest. I usually wait about 6 months to even consider looking at the new stuff.
If you decide to go OEM with a CPU get a small syrenge of the new polysynthetic(electrically nonconductive) Arctic Silver thermal grease. Here lately I have been buying retail AMD. the heatsinks for the Barton's have a copper base thermal pad applied,with alluminum fins. The fans are have been very quite and cooling is excellant for a stock fan.....