You can go Intel or AMD. As someone said above I would stay away from the integrated cpu/gpu. I have one in my Alienware laptop and it has caused so many problems.
Right now it all depends on what you want. AMD is powerful and less expensive compared to Intel. Unless you are running 20 programs movies and games at a time you don't need a i-7.
I personally went with AMD cpu, and will try out the Raedon gpu for the first time. Normally I am a Nvida fan.
Going with open box/sales I spent 700ish on my build. My video card comes in tomorrow. I built my main pc back in 2009 when the phenom II 4 cores first came out. I really haven't seen anything to bog it down, I just figured to upgrade now. With the FX-8350 it will last me another 5-6 years.
Going i-7 is overkill since nothing can stop it, besides your wallet. So kinda pointless when the i-5 will take care of any need if you go intel.
Here is the build. I had a power supply already, so that was 100 dollars I saved.
http://pcpartpicker.com/user/rais/saved/4goS
This Nepton 280i cooler is the best upgrade I have ever done. I can't hear it and my cpu is sitting at 32c while overclocked to 4.6 ghz. With a normal zalman heatsink my old cpu was sitting at 42c stock with a nice wind tunnel effect.
If you go for a intel, I would advise you to go with a i-5. I made a sample build for you. All depends on what you like.
http://pcpartpicker.com/user/rais/saved/4le9