Harshlands
Based on Harn, the role-playing game, with no (?) magic and a good system.
http://www.harshlands.net/
Armageddon
A hard desert world, where the strong survives. Some magic but not easy to obtain or use as magic users usually are hunted down.
http://www.armageddon.org/
NOTE: Both these enforce role-playing, comes down heavy on powergamers and death is permanent! One character, one life. Be prepare to die a few times if you go for a warrior type of character until you learn the system.
They are skill based. No levels, no classes (apart from at creation to give starting skills).
They have a lot of social role-playing, although they lack in number of players I guess. So, if you want to be a tailor or a carpenter, that is all possible.
They are not MUSHes, but heavily modified Diku MUDs, complete with advanced emote system, day and weather, seasons and helpful IMMs that, if asked nicely, is happy to "possess" a NPC to RP with you. And of course, sometimes they do it even when not asked, giving you quite a startle... ;)
I can recommend them both, but don't get too attached to your character - you may die, from accident, ambush or being foolhardy.
Both also require you to sign up and create a character that is to be approved before you can enter, so looking at their websites and logging on to read documentation is a good idea, as is thinking about what you want. Then write it all in your word processor and copy/paste to save yourself some time.
A couple of notes about character creation:
o They require you to register with a traceable email - no hotmail etc! The one you get from your ISP will do fine.
o The character background and description should be kept at 72 character per line, so you may want to use a fixed width font and make sure you keep the line lengths below 72.