Shopping for a mining/gaming rig

[tommorisonwebdesign]

I am considering in the near future to buy a  top of the line computer from Newegg for the purpose of mining altcoins. I have two questions: Are there any preconfigured models that will get the job done and what coin should I mine? As it stands right now I have access to free electricity though I may have to move and my circumstances may change. Intel or AMD? nVidia or ATI? Also, what altcoin is the easiest to mine with the highest ROI? Thanks in advance.