CHRISTMAS IS FAST APPROACHING, and it's high time we brought you a new system guide to fuel your holiday upgrading urges. Since October, there have been some major new product releases in the high-end market, such as the introduction of Intel's quad-core Core 2 Extreme QX6700 processor and Nvidia's GeForce 8800-series graphics cards. For this new guide, we've re-thought our higher-end system recommendations while updating the lower-cost rigs to take into account pricing and product availability changes. We've also brought a brand new system into the fold with the Couch Potato. This machine is meant to be a full-featured living room PC complete with TV tuning, Wi-Fi, quiet cooling, and even modest gaming capabilities. Read on to see our latest set of recommendations for building the right PC.