theres no difference in performance. you will need am2 for quad core though.

Besides the pin layout and feature set there's almost no difference between any 754,939 and am2 motherboard

unless your overclocking, One case fan near the cpu in the back blowing out is enough for any system.

Most of the time the psu fan is enough. 

This Alienware Area-51M has upgradable graphics.

theres a picture here

http://www.hothardware.com/printarticle.aspx?articleid=632

and review here

 http://www.technewsworld.com/story/32575.html

The 7600 oc would be better but not by very much,

I woulnt be surprised if you only got 5 or 10 fps more, if anything

$60 dollars is a good price for that card though i would buy it anyway to put in another system. 

I like the $10 (beat-up/missing parts) cases.

But thats cause i'm a cheap bastard.

This is the cheapest thing at bestbuy that you might be able to scrape by on.

http://www.bestbuy.com/site/olspage.jsp?skuId=8310008&type=product&productCategoryId=pcmcat103700050019&id=1173577987807