SharkyExtreme is a great site for hardware reviews and other discussions. Thresh's Firing Squad is one of the best sites for PC Hardware reviews. Andy Drake's BXBoards is a site with some really great reviews and discussions, particularly on motherboards. InternetAndComputers.net is one of our sponsors - a nice online computer hardware store. System Optimization Information is a great page with information on a wide variety of computer topics.
Examples are benchmark surveys, performance tweaks, overclocking information, FAQs, etc.
It gets VERY detailed an contains more information than most users would need. It also gets into troubleshooting, repair, and maintenance. PC Mechanic is a great resource for building a PC, asking troubleshooting questions, and a good number of hardware reviews. PCWatch is a daily updated computer news source. Hardware World consists mostly of computer hardware reviews, in addition to news and some general information.