new PC build need input

Hope some you you experts can help me out with my PC upgrade. I will be upgrading from a AMD 4000+ single core, 1950xtx, and 2GB ddr400. As a bf2er there was no need to upgrade as this current PC runs it smooth as silk. Now that I moved on to newer games like COD:WAW I have to cut the settings way down to play. I like to get max value for my $ and I dont plan to overclock(Im here in a OC forum because I have got great advice b4) and I also have zero loyalty to either amd/intel ati/nvidia. To save $ I want to reuse my PS 600W, HDD, DVD and the case. I also really doubt I would ever use more than one video card so keep that in mind for the mobo. So with that in mind here is some stuff I have been looking at.

Cheapest upgrade: AMD 6000+. From what I can tell this is a dual core version of my current CPU with a higher clock speed. For 85$ it sounds like it has that bang for the buck upgrade I like. For this build I need advice on mobo and ram to use. Pretty sure I will go with 4GB ram and pair it with a newer 4850/4870/260/280 vid card. So is this CPU to weak for a newer vid card? Dont really care that this is a bit outdated as I do these cheap upgrades every 12-18 months.

Mid grade: E8500. Being much cheaper than the E8600 I think this hits the $ - performance pretty good. Still its more than double the cheap CPU. I need advice on mobo and ram for this one also. Should be a nice big upgrade from my 4000+.

Top of the line: I7 920. Unless the ram, mobo and CPU is much cheaper than I think its going to be this one is out of the question. Maybe when I upgrade again in a year or two.

Any other gaming CPU, mobo, ram that I have not listed is fine also.

Thanks for anyone who took the time to read this and can help out. I will be buying these parts in the next week or two and have no clue about mobo's and ram.

Well, if you want a good bang for the buck without spending too much. I would go for an e8400, asus P5Q-pro, Radeon 4850, and 2-4 of some decent ram.

I am still pretty new here and learning heaps!!
I know everyone here recommends intel CPU's and personally I wish I had purchased one but my AMD system which is similar to your cheapest choice does more than enough for me.

I have an AMD 5600 oc'd (only when gaming) to about the same specs as the 6000 you are looking at. I got mine from 2nd hand from ebay (Australia) for $60, for me already owning an AMD motherboard, that was great bang for buck.

I am running AMD 5600 with MSI 8800GT, 4 gb Corsair 6400C4 Ram, on a msi K9n platinum motherboard.
Rather average system compare to most on here but I am a student....
Anyway I have no problems running Crysis at med-high settings and most other games on max or close to max settings.
I do have a little less strain on the CPU cause im using a X-Fi Fatal1ty Pro sound card.

I think you would be happy with the AMD if money is your priority. But i dont think its ever going to be as good as the intel.

I actually saw some goose selling an 2nd hand AMD 6400 for $80us buy it now on ebay. I found it 10 mins after he had put it up. Came back 15mins later to buy it and it was sold already... lol
If your tight like me keep your eyes open!!

Hope that helped a little