I'm assuming you want a peppy gaming rig.
I'd just grab a kick butt Gaming Card, and go with what you got.
Your power supply is fine. (If its a quality one) Even your motherboard is fine, its an AM3 board.
Your running an Phenom II with 4 cores at 3.2 ghz.
Your cpu is fine.
Your memory is fine, unless your moving up to windows 7 and doing some serious multitasking, 4 gigs is plenty of memory for a gaming rig.
I mean If you want to upgrade, I guess you can Is it going to improve your gaming experience by leaps and bounds? Not likely most games are not really taking advantage of all the cpu power you have right now.
If you want a lil extra push, you could just go buy a water cooler, slap it on your cpu and overclock it to 3.8 ghz and add a faster gaming card. Eco "Cool It" makes a decent one for $60 thats a sealed unit, quiet as a whisper and keeps all but the most aggressive overclocks, nicely cool.
You are not going to get a massively huge performance increase in games by spending $500 on a mobo/cpu/mem combo.
A killer card. like this?
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102918
yea, you will get a nice boost.
It would be nice to have a faster mobo chipset, but not sure its gonna matter all that much to be perfectly honest. I think your rig is fine.
But I would definately upgrade my video card. 6970 would be nice
Spend $250-350 on a killer card, you'll not need to upgrade for 3 more years.
When your hard drive starts filling up, throw a samsung f3 1 tb in there. $50 w/ free shipping this week at newegg. Nice fast drives.