We cleverly side-stepped Intel's Core i7 offensive in our previous guide by focusing on cheaper systems. Now that the Core i7 is out, we've revised our guide with higher-end configs that use the new hardware. And, of course, price fluctuations have given us an opportunity to freshen up our other builds. Read on to see the systems we recommend for $500, $800, $1,200, $1,600, and almost $4,000.