Oh, apparently the first release on UnReal World is shared for free by the developer
http://z3.invisionfree.com/UrW_forum/index.php?showtopic=2521
Quite different from the modern builds, and the art reminds me of MegaZeux games.

Wizard's Lair (at the bottom of the page): that's likely the first rougelike I've ever played, and I remember it as a fun piece of textual adventure full of monsters, parties, stats and manticores. Those fuckin', almost invincible manticores....

Oh, oh, just remembered
Kerkerkruip. Interactive Fiction Roguelike, less about gaining stats and random die rolls and more about figuring out attack patterns and consuming enemy skills. The dungeon's still random.

Come on, who cant remember Nethack http://nethack.org/ ? :)

I don't think nethack is a good recommendation if he get's stuck while playing angband.

I would second the recommendation of brogue. It's really easy to get started and a lot of fun.

Roguebasin is a wiki about roguelikes.

The dozens of ways to get stoned by a cockatrice... mostly by an already dead one...

Triangle Wizard. Abstract graphics, real-time action, but it's got a tutorial and a wide selection of magics.

I quite like Slash'EM. It's basically Nethack with lots of extra stuff.

Besides DoomRL that really is a must-play, I would also recommend Decker.