Online Message Boards:
Reef Central
Reef Aquarium Guide (RAG)

Online Resources:
ReefKeeping Online Magazine
Advanced Aquarist Online Magazine
Aquarium Frontiers Archive Saltwater Aquaria
Dr. Shimek on Deep Sand Beds (DSB)
Rob Toonen's Hitchhiker FAQ

Book Suggestions:

Introductory/Foundation Reef Books
Natural Reef Aquariums : Simplified Approaches to Creating Living Saltwater Microcosms
The Conscientious Marine Aquarist : A Commonsense Handbook for Successful Saltwater Hobbyists

Core Library
The Reef Aquarium: A Comprehensive Guide to the Identification and Care of Tropical Marine Invertebrates (Vol 1) - by Julian Sprung and J. Charles Delbeek 
The Reef Aquarium: A Comprehensive Guide to the Identification and Care of Tropical Marine Invertebrates (Vol 2) - by Julian Sprung and J. Charles Delbeek
Aquarium Corals by Eric Borneman
The Modern Coral Reef Aquarium vol. 1 by Svein A. Fossa, Alf Jacob Nilsen
Book of Coral Propagation, Volume 1: Reef Gardening for Aquarists by Anthony Rosario Calfo

Identification & Store Guide Library
Marine Fishes by Scott Michael
Corals of the World by Jen Veron
CORALS: A Quick Reference Guide by Julian Sprung


Other Book Recommendations
ReefCentral Book List
Reef Aquarium Guide Book List

Equipment Suppliers:

Standard Suppliers Specialist/Related
Marine Depot
Premium Aquatics
Custom Aquatic
Pet Warehouse
That Fish Place
Aquarium Products - inexpensive sumps
Aqua Culture Supply
U.S. Plastic - plumbing supply
Savko - plumbing supply

Livestock/Coral Suppliers:
Coral City
Marine Depot Live - good descriptions
Flying Fish Express
Phishy Business

Frag Suppliers/Specialists:

Dr. Mac Corals
Dynamic Ecomorphology
Rod's Reef
Lonestar Corals
Coral Farms
Carlos' Incredible Frags
CoralSandBar - $75 package deal
Greg Hiller
Aquatic Reflections
Ron Colemans small but beautiful frags

Critter/Cleanup Crew:
Indo Pacific Sea Farms - critters
E-Tropicals - clean up crew packages
Reeftopia - clean up crew packages

Cool Tanks:
Richard Durso's 180 Gallon Reef: Creator of the Durso Standpipe
Cool tank - cool tank and useful livestock reviews
Blue Ocean Designs