If you're open to building your own system but haven't done it before, Newegg's Customer Choice Awards are a great place to start:
http://www.newegg.com/Product/CustVoteProductWinner.aspx
They're a record of the most highly rated hardware each month, and, besides quality, provide a strong indicator of the parts with the best price-to-performance ratio.
You might also take a quick look through the video-editing benchmarks at sites like AnandTech and Tom's Hardware, since you have a specific use case in mind. And if you ask for help in their forums, you'll also get plenty of input, e.g.
http://forums.anandtech.com/showthread.php?p=34595700
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