Price check please

Price for what? Are you buying or selling it? Its probably worth around $200 to $250. That was a pretty good computer 3 years ago.

If you're thinking of selling that, the parts are worth more (to you) than you'll ever get for them in cash.

You could seriously just drop a Q9550 in there and have a pretty decent machine. Maybe add more RAM and a 4870 or 57xx video card while you're at it, and you'll have a gaming machine that will last at least another couple years. The fact that your motherboard supports quad core is good news for you.

Yeah but the P965 chipset was designed with Q6600 in mind as the quad. It MAY support Q9xxx series with updated BIOS but if its an early revision P965 you are limited to the 65nm chips.

I am selling, I built it about 3 years ago  

Interesting idea, I was all ready to build a new machine with an i7...

Well, according to the specs on ASUS' site, that particular board is supposed to accommodate 45nm chips, and lists the Q9550 on its CPU support list: http://asus.com/product.aspx?P_ID=bswT66IBSb2rEWNa

Although you're right -- it's certainly worth double- and triple-checking that kind of thing, because it's pretty lucky for a board that old to support modern-day hardware. You definitely made me go back and look at it again.  

There may be something I missed, but it sounds to me like when they put together this particular board, they meant to market it as "compatible with any CPU that comes out in the next two years" or something to that effect, and it might have actually turned out that way.