im not sure, but then again graphic cards can work by themselves but motherboards are not "stand alone" in the sense that its selection depends on wat processor u're looking at, the RAM, and the chipset which goes well with ur selection. thus its hardly possible to offer a 'guide'
I was leaning a little more towards the "basing a system around a motherboard" instead of basing the parts around the cpu like you are. After I read up on alot of computer ish it seems that any halfway new processor these days isn't going to make or break the system so long as it isn't a 300Mhz generic brand. If you need help just give as much info. as you can about what you would like to do with the computer and the budget. After that you will get alot of oppinions. What I got asking this same question a couple weeks ago was the abit IS7 and the asus p4p800 regular or delux models. You might be using the computer for something different than I was however. I would recommend checking out tom's mobo reviews, he must know something about computers if he started this site and growing to be as big as it is now. good luck.