I agree with moribund and several others above.  If you want the TYT community to help out with suggestions, we need more info.  We want you to succeed, but that involves making the right purchase choices with limited funds.

Are you converting a single large video and need it done fast, or converting many videos a day and can't get through them all quick enough?  What software are you using, and encoding/transcoding to what formats?

The Core i7's are really fast chips, but you do pay a premium.  For less you can get quad-core Core 2s, AMDs, etc.  You need to know if your software utilizes multiple cores/threads when encoding, is it optimized for SSE, etc. (otherwise you are paying more for a chip that isn't fully utilized anyways) Some software is now utilizing the graphics cards to speed up encode, but with limitations (http://www.computerpoweruse r.com/editorial/article.asp ?article=articles%2farchive %2fc0909%2f40c09%2f40c09.as p&guid=72B633282C374436 823A4F40BD3D300B)

Before you blow limited funds on one quick machine, make sure you aren't better off buying 2 or more machines for the same price and getting more throughput during the day, etc.