CoD:MW2 at 1440x900 with everything maxed out. FPS equal, or a

I plan on building a new gaming PC in the next few months. I am going to make sure I can play CoD:MW2 at 1440x900 with everything maxed out. With an FPS equal, or above, 72fps.

But I don't know too much about what sort of motherboard I am looking for. I can't tell which is a good, or bad one. Or which company makes the best boards. I don't need anything super, maybe something mid to high end. I really don't want to spend over $150. I would prefer an AMD (AM3) board with the ability to run two ATI cards in Crossfire (Is there a difference between Crossfire and Crossfire X? Or is it the same thing?)

I plan on this CPU: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
It's an AM3 Quad that is clocked at 3.2GHz with 4x512KB L2 Cache, and 6MB L3 Cache. All for a little under $200.

I was going to get a Tricore, but I figured it wouldn't be long until games/programs really start using quad. I already play a few games/programs that will use all 4 cores. So I have decided this as my CPU. Unless there is something bad about this CPU?

As for RAM, I don't have the slightest clue... It would obviously be DDR3 because I will be running an AM3 setup. And I would prefer to have 6GB (I might go with a 64bit OS) with over 800MHz (Maybe 1333MHz or better?). Although, I'm not too sure what the difference in timing and voltage is. For instance, what does 4-4-4-12 mean? (That was just an example. I'm not too sure if that is an actual timing on RAM)

As for a Video Card. I was going to wait until ATI and NVidia are done releasing their new cards. I might grab a two HD 48xx's and run them in Crossfire.

Short term needed:
CPU
MOBO
RAM

Thank You to anyone who responds!

A case and PSU I really don't care about too much. I'll get whatever case that keeps everything cool and is built solid. (Maybe an Antec or CoolMaster). As for the PSU, I plan on something either at 750watts or more.

I was hoping I could get some suggestions for a Motherboard, and RAM. (And maybe a Video Card(s) and PSU)