Lurked for quite a while here, but I just had to register so I could rep my favorite roguelikes.
(Linley(Henzell)'s)Dungeon Crawl "has superb, deep tactical gameplay, innovative magic and religion systems, and a grand variety of monsters to fight." The above links to the Stone Soup variant which arose to address the desires of the players when vanilla Crawl development slowed to a halt. Even more fabulous, a player by the name of Enne Walker coded up
a version with graphics!

Utilitarian graphics even! Somebody finally had the bright idea that 32x32 sprite in 256 colors can convey more info than a single character! Your sprite changes based on items equipped, and a long sword is easily distinguishable from a falchion using *just your eyes*! Imagine!
Or, if you seek a more old-school sensation, you can't go wrong with
vanilla Angband. A new dev took the helm a year or two ago, and it's looking good so far.