Suggestions for gaming PC build

Hello everyone. I am looking to build a mid-level gaming PC. I'd like to keep it around $800 or so. I am planning on doing this over time and not at all at once so if i need to up the budget or whatever I can. I'd like something that would be able to play WoW, SC2, and the new Simcity on max settings. I usually leave my first person shooters/sports to the console. I know how to build it I guess as I look through all the parts and such I don't feel like I'm getting my value.

In addition if you have a build you can suggest to get this done at $500/$600 please share it. I don't object to saving money.

I also have no intention of overclocking. My system will hook up to dual monitors at 1680x1050.

Didn't see this before. Guess I should learn to read.

Approximate Purchase Date: Over the next few months

Budget Range: $800 Total

System Usage from Most to Least Important: gaming, watching movies

Are you buying a monitor: No

Parts to Upgrade: (e.g.: CPU, mobo, RAM) **Include Power Supply Make & Model If Re-using**

Do you need to buy OS: No

Preferred Website(s) for Parts: Doesn't matter

Location: City, State/Region, Country - Cincinnati, OH (We have a microcenter)

Parts Preferences: Intel

Overclocking: No

SLI or Crossfire: No

Your Monitor Resolution: 1680x1050,

Why Are You Upgrading: Current PC is 7 years old Dell XPS 410. It needs to be retired/upgraded. I think retired is a better option.