I'll add some other -bands that I think are definitely worth checking out. The ones with the asterisk are my personal favorites.
1)* UnAngband: The dungeon generation is wonderful, and has some nice colored ASCII. They do some interesting things with decorating the dungeon. It actually feels like a dungeon, rather than a series of generic hallways and rooms. It also has more 'room descriptions'. When you walk into a room, it will give a small description. Reminds me of some tabletop DnD. It has mouse controls too.
2)* TinyAngband: Similar to Quickband, though I think the town is more interesting, with more services.
3)* ZAngband: A more indepth -band. Theres a randomly generated wilderness, towns, and various dungeons.
4) Furyband: Lot's of races and classes, like the basilisk. Some of them are kinda silly. It reminds me of the orignal ToME.
5) Halls of Mist: Already mentioned. Like vanilla Angband, but some interesting features. On any stairs down, you can choose to dive down 1 level, or up to 3. Any upstairs, regardless of level, will immediately take you back to town. When you head back to the dungeon, you can choose to either head back to the same level, or the level above or below it. There's also phantoms that appear that will attack you if you linger too long on the same level. I have yet to encounter them, and I like to take my time, so it's not exactly trying to rush you.