List of Good Roguelikes

Necklace of the Eye - This is not actually a Roguelike, but instead it is a program that allows you to give 2d or 3d graphics to a console based Roguelike
http://roguetemple.com/z/noteye.php

ADoM - A classic Roguelike which features a world map, a quest tree, multiple endings, and a detailed character generation system.
http://www.adom.de/

Alan's Psychedelic Journey - A coffee-table Roguelike in which you attempt to make your way through a dungeon while eating every mushroom in sight
http://exador.sourceforge.net/apj.html

Ali Baba's Cave - A stealth based coffee-table Roguelike.  Collect treasure, rescue the princess, and try to avoid combat when possible by staying out of the light.
http://www.stambouliote.de/alibaba/

AliensRL - Based on the movie aliens, this coffee-table Roguelike is action packed and features sound effects
http://alien.chaosforge.org/downloads

Angband - The classic that inspired the Blizzard game "Diablo".  It takes some inspiration from Lord of the Rings and is fairly straightforward.
http://rephial.org/

A Quest Too Far - A coffee-table Roguelike where you are an old veteran adventurer who starts out very powerful but becomes weaker as you gain experience.
http://www.randomstuff.org.uk/~geoffrey/roguelikes/aquesttoofar.html

Berserk! - This coffee-table Roguelike is a fantasy survival game of tactical bloodshed, loosely based on Kentaro Miura's Berserk manga.
http://berserk.chaosforge.org/index.php?module=downloads

Brogue - Simple yet elegant, and very, very cruel. Familiar character based graphics are brought to a new level. You must play this.
http://sites.google.com/site/broguegame/

CastlevaniaRL - Castlevania lovingly made into a Roguelike. Music, classes, monsters & more!
http://slashie.net/page.php?6

Cataclysm - Post apocalyptic survival with detailed inventory and combat systems and surprisingly interesting/expansive crafting.
http://whalesdev.com/download.php

ChessRogue - If you are a fan of chess, than this coffee-table Roguelike is for you!
http://chessrogue.sourceforge.net/

DoomRL - It's DOOM! Guns, health kits, levers, more guns & a new graphical update so there's lot's & lot's of blood! All as a turn-based Roguelike!
http://doom.chaosforge.org/

Dungeon Crawl: Stone Soup - This is a straight forward Roguelike in the spirit of Nethack.   It contains many classes/races, a nice interface, and multiple game modes.
http://crawl.develz.org/wordpress/downloads

Elona - Detailed, huge RL with a JRPG theme.
http://homepage3.nifty.com/rfish/index_e.html

Frozen Depths - Featuring solid gameplay, this is a combat-oriented Roguelike game that takes place in a cold fantasy world.
http://koti.mbnet.fi/frozend/download.php

Gearhead 1/2- MECHAS!
http://www.gearheadrpg.com/
(To get GH1 to run properly download http://sourceforge.net/projects/gearhead/files/gearhead/1.100/gh-1100-sdlimage.zip/download and unzip it to the same directory as arena.exe)

Gruesome - "It is pitch black. You are likely to eat someone..."  This coffee-table Roguelike is stealth based, incorperating light sources and a FoV for NPCs
http://www.gruesomegames.com/

Guild - A very unique Roguelike in the sense that it gives you control over a party of 4 adventurers rather than the traditional solo dungeon diving
http://www.roguetemple.com/guild/

Hydra Slayer - Carefully select what weapons to use to cut off all the hydra's heads.  Basic math skills are needed to get anywhere in this game.
http://www.roguetemple.com/z/hydra.php

IVAN - Iter Vehemens ad Necem
RL with a sense of dark-humor, I discovered here & love it.
http://ivan.sourceforge.net/

Nethack - One of the granddaddies of the genre.
http://www.nethack.org/

NLarn - This project took re-coded the Roguelike "Larn" from scratch and the result is a more stable and aesthetically pleasing version of a classic.
http://nlarn.sourceforge.net/

Omega - A somewhat obscure but very in-depth Roguelike which features a world map, a questing system, and a good sense of humor
http://www.alcyone.com/max/projects/omega/

POWDER - A simple but fairly difficult roguelike in the vein of Nethack. Great for beginners to the genre, and also available on the NDS,GBA and PSP.
http://www.zincland.com/powder/index.php?pagename=about

Red Rogue - Flash based platformer style of RL, still being dev'd, so new features always being added.
http://robotacid.com/flash/red_rogue/

Rogue -  The original Roguelike!  It may lack complexity, but without it, none of the other games in this list would exist.
http://rogue.rogueforge.net/

Rogue Survivor - Zombie themed RL where the goal is survival.
http://roguesurvivor.blogspot.com/

Sil - A complex roguelike that boasts a very by-the-book Tolkien theme, with strong emphasis on tactical combat and discovery.
http://www.amirrorclear.net/flowers/game/sil/

Slaves to Armok II: Dwarf Fortress - Besides the excellent mining & building main game there is an adventure mode.
http://www.bay12games.com/dwarves/

Slash'EM - This project is Nethack with added classes, races, items, spells, techniques, creatures, and dungeon branches
http://slashem.sourceforge.net/

Sporkhack - This project is Nethack with some modified code to improve game balance, making it easier in the early game and harder in the end game
http://sporkhack.com/

T.o.M.E. - Featuring the T-Engine, this Angband-based Roguelike has unlockable content and support for player created modules
http://te4.org/download

You Only Live Once - This coffee-table Roguelike has a unique combat system(attacks never miss) and a nice dungeon generation system
http://www.zincland.com/7drl/liveonce/

ZeldaRL - Based on the hit video-game franchise "Zelda"
http://slashie.net/page.php?22

For a more complete list of Roguelikes look here
http://roguebasin.roguelikedevelopment.org/index.php/List_of_roguelikes_by_name