So Im looking to build a fairly powerful gaming rig but I have never built one before and Im tired of prebuilts. The probably is Im not really smart on parts or what actually qualifies a good rig. Im looking in the 500-600$ range for parts and case and for a monitor I have a decent small flatscreen tv. Would that work as a monitor?

Is there a site that can help me decide on parts within that budget.

http://www.logicalincrements.com/

I recently built my first PC for about $700 and I used this site as a guideline.

Plus the site moderators are pretty active in the comment section and they're very helpful.