With a high-end system I'd go with 8GB of RAM and a 64-Bit OS, so not only will you have a strong gaming platform but a better equipped workstation as well. You may get into 3D modeling, CAD, or Virtualization (finding that you can run mulitiple instances of Vista, XP, and Ubunto simultaneously inside a 64-BIT host via VMWare can get addictive). Takes a reasonable disk-sub system but you've got money for a decent hardware-based AID 0 or RAID 5 + backup. ...of course 8GB of DDR3 isn't going to be economical....
Again, you may be able to get a stronger system if you're willing to change your specs (a 64Bit OS will appreciate 8GB of DDR2 more than it will appreciate 4GB of DDR3) and you'd have more money available to upgrade to a Nahelam platform, should you wish to upgrade to the latest and greatest. You could also save a notable amount if you went with a Q9450 as opposed to the Q9550. ...or....or ....or consider going with a dual quad-core setup that will get you more processing power than you'll likely be able to find a use for today. You'd be closer to that All-Out rig I think you're aiming for.
There's so many ways to spend $3.2K on a strong system it hard to cover them, as you can see. I would definitely look to 8GB of RAM in a super strong platform that I expected to be happy with for 3-4 years, and might consider 8 cores with a socket 771 board. I'm not sure I've seen anything that would lead me to believe that 4GB of DDR3 would be the better investment over 8GB of good DDR2. That might sound like gross and wasteful overkill today, but it won't be in just 1 year. In a year you may not have the newest system but you'd damned well would have a strong one.
Graphics power? Video cards come...and they go. What's hot right now aint gonna be hot in 5 minutes. With that in mind I can't recommend that you go out and invest a good portion of your money on the highest of the high-end gaming graphics solution that will be obsolete in 6 months. In fact, if that were me, it'd annoy me...$600+ dropped on a now obsolete graphics solution. Better to go
mid-to-high end at a reasonable cost so you can upgrade the video sub-system more often.
Just one possible flavor of the head of a hardcore rig:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813121330 = $660
or
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131272 = $500
http://www.newegg.com/Product/Product.aspx?Item=N82E16819117145 X 2 = $970
http://www.newegg.com/Product/Product.aspx?Item=N82E16820148189 x 2 = $500
...mate something like that with nice graphics, a good PSU, nice storage, and I nice case with the at least $1K+ left over and you'd have that over-the-top $3.2K system. There's so many options for such the enviable position you've found yourself in...just depends on how you want to spend the paper and what you really want.
A nice system with money left over for something else later or the baddest rig you can slip into right now?
I don't believe you told us what would be your primary task/goal with this rig, cause you don't need to spend $3.2K to enjoy Crysis and AoC.
Think it through.