Realms of Despair - A client devloped for ROD that works with windows.  Small download, easy to install and simple to use.  Great for people new to MUDs or away from home and dying to play.

zMUD - An excellent MUD client.  Easy to manage, lots of little features to make game play more enjoyable.  Comes complete with a list of playable MUD's across the world.  Comes very cheap from ZuggSoft and is updated frequently.  Once purchased all future updates are free.  Download a 30 day free trial (Version 6.16)

Equipment Database - A large database of in game and out of game equipment, items, and weapons.  Allows for easy filtering and even has a place to build your characters equipment and shows you how the equiped item will affect your over all character. (Coming Soon)

SMAUGwiz - A downloadable mud to help you get started with building one of your own.