If you can deal with a few really awful puns (they're his trademark), then you might like The Lonely Goatherd by speakr2customrs. It's set after the end of Angel, and focuses on Spike and Vi (one of the Potentials). He also wrote a very well done Spike/Willow, "Angel of the Morning," which goes AU partway through season 6 of BtVS.

liz_marcs writes mostly Xander-centric fic, but she uses Faith a fair bit as well. Some of her earlier stuff is a little bit iffy (and the time-travel story is just 'ack, no, get it away from me!') but I like a lot of her more recent stuff.

missmurchison wrote a really nice Spike/Tara story ("Quick and Bitter, Slow and Sweet"), and a couple of marvellous Spike/Joyce stories.

Um. And I have now run out of recs, since you don't want Spike/Buffy, and I only dabble at the fringes of BtVS and Angel anyway.