Audio Links
The internet is a mine of information for audioholics, and some of it is actually useful.

Here are some of the sites I've found particularly good:

Linkwitz Labs - Everything you've always wanted to know about dipole speakers

HT Guide - Especially useful for DIY planar and dipole speakers

Madisound - The best speaker building site on the Net

DIY Audio - Also has useful info for builders

Home Theater Forum - DIY sub central

AVS Forum - The best forum for general HT, especially projectors and HTPC

LSDG - A great resource for information about drivers

Audio Asylum - Know thy enemy

DIY subwoofers - Lots of subwoofer info

AV Guide - Great music reviews from The Absolute Sound, silly equipment reviews

Audiogon - The best used equipment site on the Net.

eBay - The best auction site if you know what you are doing

eCoustics - Good compilation of online reviews
(Sorry about the alignment problem, but I like the colors)