DC Comics - The Official Website of DC Comics.
The Unofficial Guide to the DC Universe - Great resource for DC titles & characters.
Newsarama.com - Best site out there regarding up to date comic news. It contains also reviews, message boards, and more.
CBR Links Database - Extensive collection of comic related links sorted in various sections.
The Green Lantern Corps - Simply amazing website dedicated to the Green Lantern legacy easily my fav GL related website.
Marvel Family Web - Most likely the best website dedicated to DC Comics/Fawcett Captain Marvel and the Marvel/Shazam Family.
Superman Homepage - Greatest Superman fan site on the net.
Uncanny X-Men.net - By far the best site dedicated to the X-Men and related characters.
Superhero Chat - My favorite superhero related community forum with lots of great debators.
Alvaro's ComicBoards - Has a vast ammount of character boards to enjoy.
The Comics Edge - Fairly new and small comicbook community forum but definitely a good one.
Wing-Nuts Forum - Small but very dedicated Nightwing centered fan forum that you can go to talk about Bludhaven's guardian.