www.2cpu.com one of the best and most respected. Been around a looong time, and still keeping it real. The Networking and Hardware sections are very active. Lots of really heavy duty hardware. Gaming is important, but these guys are more into raw power than eye candy.
www.murc.ws The Matrox Users Resource Centre: used to be the Mecca for those in search of knowledge about Matrox, but since Matrox dozed Mecca and barely manufactures anything these days, it has become a rather nice gathering spot. General Hardware (for the bleeding edge.) and Alternative Lifestyles Forums for the *nix junkie... A robust Off-Topic forum there too for those who like to abuse (and be abused by) left wingers - there are some pretty heavy hitters there, so beware. Flaming is not encouraged, but strongly worded debates are the norm.
www.linuxcompatible.com and it's sister site
www.ntcompatible.com are great sites for daily news.
www.smoothwall.org Smoothwall is a linux Router distro, but jump into their very active forums and you should be able to find nearly anything regarding Linux Shell Commands. Very Friendly People, and a GREAT Distro.