Noone ever tried Discworld MUD?
It's based on Terry Prattchet's Discworld series of books, though you don't need to have read any of them to enjoy the game.
It has a wonderful parser that totally ruined any other mud for me. You can type commands such as "get balls except yellow balls from second sack", instead of working with id numbers or very specific syntaxes. I also love how there's no need to eat or drink anything at all. Even though there's more than plenty of food and booze around.
The game is quite combat-oriented, though there is a lot of room for crafting, exploring and generally being a pleasant chap. Players can only kill or be killed when they register as playerkiller, so it's safe to wander around, mostly. Assassins have to go PK once they pass the 'Run', though. A final test after which they can complete contracts set on other player's heads.
Levels are based on the skills you gained relevant to your guild, so it's really just a level-less system. A wizard can live by the sword if he wants to, only casting spells for defense and portalling around. Some guilds have some sort of player-run system, though if you don't want to bother with politics you don't have to at all.
The world is rather large, having a giant overworld based on the official Discworld Mappe, with quite a few large cities on it. There's about 5 or 6 languages you can learn to speak and write, some being exclusive to certain guilds. Travel is often done by asking a wizard or priest for a portal or passage, witches tend to just zoom around on their broomsticks. There's a 'map' command that shows you the immediate surroundings anytime, anywhere. And with some direction skills, you can navigate using inworld maps and even mark your own places on them.
Warriors get lots of commands to track people, make people soil their pants with a warcry, go berserk and chop heads off.
Thieves get to steal the shirt from under your coat and sneak around all over the place. They can legally steal up to a certain amount inside Ankh-Morpork, the biggest city, since their Guild is official and pays taxes to the government. Anything outside the city walls is free for the taking though, barring local laws.
Assassins get to mix poisons (anyone can do that, though accessing the poison labs is rather tricky) and take out contracts on other players. Various sub-guilds have their own methods.
Witches get to be female-only, brew healing teas, fly around on broomsticks, make objects think they have a new name, make illusions and throw swarms of bees and stuff.
Priests get to pick a God to worship and use said God's rituals, imprint said rituals onto objects so other people can use them, and pray.
Wizards get to remember spells such as portalling, throwing firebunnies, changing people into frogs, crafting illusions, enchanting weapons, scribing spells onto scrolls for others to use, and so on...
Most commands and all skills can be learned by anyone, though a few abilities are exclusive to each guild.
Only available race is human, but nothing stops you from just saying you're a dwarf.
If you'd like a tour, just look for 'Rhodan'. I'm a wizard, so I can easily take you to all the pretty places. Ever wanted to know what a dwarf mine in the middle of a human town would be like?