Heya all I was scanning the internets for some older classics I enjoyed and found someone had rewritten the Dungeon Master series for modern pc's (the originals started in 1987 for the Commodore Amiga!!). Definately an oldie but goodie imho, classic dungeon exploration in first person. The graphics of course are dated but some of us can still play games without next gen graphics to stare at. You start by choosing 4 heros, then descend into the depths, food and water is an issue, as well as light so you need to manage your resources (although its not as bad as some games where you'll starve in 5 minutes without food) . Some puzzles, the usual spinning floors (to confuse mapping), monsters, traps, etc... not sure but I think the later games added a mapping feature.
K2 I figure you've probably played at least one in this series, might want to grab your graph paper and give em a replay
http://www.ragingmole.com/RTC/index.htmlTim~