Gaming Uprade AMD chip $500 budget

I'm planning on buying myself a few parts to replace my aging fx-60. I plan to use the mb/cpu in my HTPC and if my budget allows it I'd like to switch over my current 8800gtx XXX XFX 320mb too.

So...onto what i have. Athlon FX-60 OC'd to 3.2ghz with a vigor gaming monsoon 2 tec cooler on a Asus A8N-32 SLI with 2 gigs of DDR memory, the aforementioned 8800gts oc'd edition in an lian-li PC-65B case and a CoolerMaster HX550 psu

I think my biggest bottleneck at the moment is coming from my DDR memory, so I'd like to jump ahead to DDR3 if possible, even if the benchmarks show the improvement is negligible. I use onboard sound now and plan to do so with this build. I have a couple of sata HD's and can carry them over too if needed. I was thinking about a x3 720 BE as the cpu; decent price and should prove a good, easy OC'er. I'd like to go with 4 gigs of memory if possible unless the majority assumes 2 gigs is still enough. I will be making the move to Win 7 with this upgrade as well. I haven't seen a real use to crossfire/sli for the cheaper cards yet....it always seems technology moves so fast that with just a few bucks more you can buy a next gen card that gives you about the same performance as buying a duplicate older card would give you, minus the added PSU requirements and heat. I haven't been paying much attention to the hardware market in the last year or so, so please let me know if any of what i've said here is wrong.

As I said above, i plan to move the core of this system to my HTPC, so if a video card is purchased, i'd like to be able to move my current card into my HTPC as well. This means needed a new PSU as my current HTPC's, does not include a pcie connector.


APPROXIMATE PURCHASE DATE: Before Christmas

BUDGET RANGE: 500

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Gaming, Web Browsing

PARTS NOT REQUIRED: Keyboard, mouse, speakers, monitor, case, HDD, PSU/GPU if i replace one, i'd like to replace both

PREFERRED WEBSITE(S) FOR PARTS: new egg

PARTS PREFERENCES: AMD Cpu, No preference on GPU

OVERCLOCKING: Yes, probably not crossfire or sli unless these new cards make it worth it

MONITOR RESOLUTION:1650x1080

ADDITIONAL COMMENTS: Future proof as much as possible preferred, last upgrade i went from an athlon 3200+ on a 939 board to the best chip available for that socket 2 years later, fx-60

Any advice will be much appreciated.

Er, doesn't he still need a mobo??

Edit: my bad, I didn't see that it was a combo deal.