Auction/Trade/Buy/Sell
Bartertown ....Gaining some steam. Neat way to trade.
Ebay .....by far the most important marketplace for buying or selling rpg
Heritage Auction Galleries....Auctioneer site specializing in art and antiques. Sell a lot of fantastic fantasy/sci-fi illustrations.
Newsgroup ....Ye olde buy/sell space on the Internet since the 80's.
RPG Marketplace..... Recent start-up. Community oriented alternative to eBay.
Wargamer's Market ...Gaming and Minatures marketplace.

Auction Tools
Toolhaus.org....eBay tools.
AuctionSieve ....eBay tools.
AuctionStealer ....Sniping software
Just Snipe ....Sniping software

TSR Borderlands Keep (TSR interests)
The Acaeum....Comprehensive collector guide for all OD&D and 1st edition D&D gaming items.
Dragonsfoot ....Free fantasy roleplay material for AD&D and Lejendary adventures.
Greyhawk Online.... Lots of world of Greyhawk content.
Kargatane ....Unofficial fansite catalogue of Ravenloft setting. People, places, monsters, artifacts, etc.
TSR Archive ....Comprehensive visual catalog of TSR D&D products by gameline and world setting.
WoTC ....This is where the mighty TSR was absorbed and was again swallowed by Hasbro, Inc.

RPG General Provisioner

Afterglo.... nonTSR index with information. This is the saved version via wayback machine.
Afterglo2.... nonTSR Dungeons and Dragons titles by publisher with pictures and information.
Arduin fan site....All things Arduin
Ariel Archives...a site devoted to roleplaying games, expecially the Autralian Roleplaying community.
Chaosium .... Publisher of many rpgs including Call of Cthulhu
DreamBorn .... Kent Krumvieda's Tarracina items and more.
Dragon Tree Press ....Publishers of the World of Delos and later Arduin titles.
Emperors Choice ....Publishers of Arduin Grimoire titles by Dave Hargrave.
Flying Buffalo ....Publishers of Tunnels and Trolls amongst others.
HeroQuest Glorantha....site devoted to Heroquest, Glorantha by Issaries.
Judges Guild ....The main page for Judges Guild resurrected. Check into the forums for fun.
John Kim's Encyclopedia of Role Playing Games.... and other interesting articles.
Mayfair Games ....Publisher of many fine D&D scenerios.
Midkemia Press ....Distinguished old school publisher of generic aids and scenerios.
Pen and Paper ....visitor-contributor driven database site. Very well maintained. Excellent gaming bio section.
Pied Piper Publishing ....The home of The World of Kalibruhn™ and other material written by Rob Kuntz
RPG.net .....A slick and comprehensive, user supported index and wiki of RPGs and TSR items.
Skyrealms of Jorune.....Jorune resource
Steve Jackson Games ....Official SJG website. Makers of GURPS, etc.
TravellerBibliography.org ....Official SJG website. Makers of GURPS, etc.
Tunnels and Trolls ....Unofficial fansite for T&T gaming and collecting.
Yog-sothoth ....Call of Cthulhu. Tidy community.

Adventurer's Press Archive (fanzine and magazine)
Alarums and Excursion ...Lee and Barry Gold still at after all these years.
RPGMagazine Indices ....Shannon Applecline's page on mags and fanzines.

Wargamer's Guild
Wargames Research Group ....containing a number of reprints of their early productions.
Board Game Geek ....for all the board wargamers out there
Boone's Wargames Home Page ....An archive of early wargame magazine covers and contents.
Universal General ...Particularly noteworthy is Tony Bath's Hyborian Campaign page
The Courier Timeline ... Historical summary.
The SPI Compendium ....Greg Costikyan's SPI index
Web-Grognard ....wargaming site. Particularly interesting is the index for Avalon Hill General.

Miniatures Smithy
Blackmoor Miniatures Home....selection of painted minis and hobby info..
The Blue Mule.....
The Miniatures Page.... A web-magazine for Miniature Wargamers
Heritage Dungeon Dwellers.....
Frothers Unite!....
Cool Mini or Not.... Self descriptive. Thumbs up or down.
Otherworld Miniatures ....New 'old school' miniatures based on popular D&D visual icons.
Stuff of Legends ....Very comprehensive effort devoted to minis.

Art
Illustration Exchange .... trading and discussing contemporary fantasy illustration.
Northern Star Art .... for-sale pages of scifi and fantasy contemporary illustration.
Worlds of Wonder .... comprehensive dealer of scifi and fantasy contemporary illustration.

Retailers
Noble Knight Games .... buys, sells, and trades new and out-of-print Role Playing Games, Board & War Games and all things game related.

General Other
Blackle.com..... Everyone know Google is prob the king in search engins these days, but how about going environmentally friendy and use blackle.. the energy saving google
BCE Mylar ....Super archival protective sleeves in all sorts of sizes and styles. Put the expensive ones in these.
Collectibles Insurance Agency, Inc. ....In case you would like to insure your collection.
Demian's Gamebook Webpage.... international reference guide to interactive books, solitaire role-playing, and game-inspired fiction.
John H. Kim's Role-Playing Page ....Amazing resource on numerous aspects of game theory and miscellany. Massive links page, encyclopedia of game companies, many a thoughtful essay.
Wayback Machine..... Page gone from the net? then use the wayback machine.. excellent for finding old web page info
Wikipedia..... General encyclopedia with many articles pertaining to all gaming interests.
The Play Generated Map and Document Archive ....Archiving home-made manuscripts and maps for role-playing games.

History of Gaming
A Brief History of Roleplaying Games ....Excellent and accurate historical dissertation on role playing as it relates to D&D and FRPG's.
History of Roleplaying by Astinus .. ..article in a roleplaying zine called Places to Go People to be. Multiple installment.
Literary Sources of D&D ....Most excellent compilation of classic literary origins to elements used in D&D.
WorldNet....Shannon Appelcline's perspective on history of gaming with a psycho-analytical approach. Several other dissertations and directions to explore on this site as well.

Theological/Psychological
Game Hysteria and the Truth: Part One by Michael A. Stackpole ....perspective on religious zealots vs D&D. Stackpole's advocacy work once called him to the stand at a murder trial as an expert witness. Not too be confused with the Tunnels and Trolls Stackpole (ummm, we think so anyhow)
Studies About Fantasy Role-Playing Games ....Bibliography of a variety of Role Playing directed dissertations.