Presumably you watch "Angel" already? You might want to try Joss Whedon's other show, "Firefly", which is currently showing on Mondays @ 2100 on the Sci-Fi channel (and repeated late night and on Fridays - evening and late night). It's a few episodes in, and you've just missed the "catch up" session, but I dare say they'll do another one. If not, it's fairly easy to pick up on what's going on. Unfortunately the show has been cancelled, but there are plans for a movie. Basically it's a western set in space, so you may not find it to your taste (it's also quite slow-paced). However, the writing and humour is similar in tone to Buffy. I enjoy it, but appreciate that it wouldn't be everyone's cup of tea. Apart from that, I can't think of anything similar - the wanabees (Dark Angel, Charmed) leave something to be desired. You mentioned 6 Feet Under, which seems to indicate that you are looking for drama with humour, so you may enjoy "Farscape" (again cancelled - sob - but at least you have four seasons to choose from). Be warned that it takes a few episodes to "get into" 'Scape, and depending on what season is being repeated on SciFi/BBC atm, there may be quite a lot of back-story.