E5200 or AMD build?

Currently, I have an AMD64 X2 3800+(running at 2.2) + a Geforce 7600GT as my main computer/gaming rig. I built this system in early 2007 and I think it's time for an upgrade. My budget < $200

Initially, I wanted to stick a Phenom II into my computer but my current mobo (Gigabyte GA M51 GM S2G, socket AM2) apparently only supports up to an AMD X2 6400. I doubled checked with Gigabyte and they confirmed that Pheonom II's don't work on this mobo ;(

Well now, I'm torn on what to do to upgrade my performance. I wasn't initially thinking about getting a new mobo but I saw this great deal at Fry's for an E5200 + 31g mobo for $99. If I pair that with a new Radeon 4670, I figure I'd have a system good enough to last the next 1-2 years (I don't have the power cable for a 4830).

I can also opt to keep my current mobo and just stick an AMD Athlon X2 6000+ ($99) or a X2 5200 ($59) and save a little.

Finally, I could also just go for a Phenom II 720 + 790gx mobo but then I wouldn't have the funds to add a new graphics card.

This build is for SC2 + D3 + CS:S + TF2 + L4D, among others.

Well truth be told, I always got the impression that my CPU was bottlenecking even my puny 7600GT so I don't see how big of an improvement just a better graphics card could make. In my estimation, the 4670 would be enough for my needs (1440x900) and at this point, one of the only items I'm pretty certain about getting.

My main cause for confusion is the e5200 since the last Intel chip I've used was a P4 @ 1.7 ghz. How would it stack up against a X2 5200, 5400 BE, 5600, 6000+?

I'm sure a 4850 would definitely be a ginormous boost to my performance but a 4850 + new PSU would run me around $150-$180. For the same cost, wouldn't I gain a bigger boost from a e5200, g31 mobo + radeon 4670?

To give you an idea of how slow my cpu is, I sometimes hit 100% cpu usage when AVG virus scan is running

I have an E5200 and its a great chip. It can overclock very easily to give E8xxx-like performance at a fraction of the cost. I have it in a micro ATX board as well (<£40) and it runs at 3.2Ghz 24/7 no problems. I have ran COD4/5 and DOW2 maxed out (19'' monitor) with a 9800gt. Since a 4670 isnt that much worse than a 9800gt, as long as your willing to make some graphics sacrifices 6+months down the road, then given your budget i'd get the E5200/4670 combo. You dont mention wether your budget includes the sale price of your old hardware, because you may find you get a bit extra to put towards your new build by selling it.

So much for my budget...I couldn't control myself and ended up buying a PII 720 + biostar 790gx mobo + Radeon 4830 + antec earthwatts 500w psu...TOO MUCH TEMPTATION...