Dungeon Crawl Stone Soup and Cataclysm: Dark Days Ahead are the best roguelikes I keep coming back to after years, and getting full-on obsessed for a few weeks.

DCSS webtiles is incredible and I've missed something so effective and well designed in any other roguelike. Playing online is so much better, especially when you make use of one of the help bots and have people spectating your game while making the orbrun or during a hairy situation.