What is the best CPU to buy; Intel or AMD?

I personally use computers with Intel chips, I've never had an AMD.

Any thoughts?

It seems to depend on the application. For pure number crunching, I believe that Intel has the advantage. Where some sort of graphics-type crunching is required, AMD seems to do better.

I would think the Operating system has an even bigger part to play. If you know how to tweak Linux 64-bit, it would appear to give your machine a real boost. I expect the downside to be the heat generated.