I wouldn't consider the bands in this thread "real folk," but art bands using folk styles mixed with art music. Real folk, strictly speaking, shouldn't even be a product or something that is theorized about and learned, though of course with mass media, global culture etc. it's become commodified too. Nothing wrong with that really, just different.
That said, Comus - First Utterance has been blowing my mind lately, and I'm sure I'm not the only one around here because it was someone on this board who recommended it to me.
Other stuff like the Incredible String Band, Fairport Convention, Forest (late 60s/70s British band), Bob Dylan, and so many others are starting to pique my interest lately. Then there's that Stan Rogers guy I reco'd once and pretty much nobody listens, he is a definite favourite of mine.
Then we get into the free-folk improv jam bands that seem to exist all over the world these days. Finland has a huge scene(Avarus, Uton etc etc), California ain't far behind, Japan has a bunch of great music (all I have is one album by some folks called L - Holy Letters). The list goes on.
That Chinese stuff Tully uploaded was pretty damn good too, very percussive, with lots of subtle rhythmic changes and shit going on.
The only Sol Invictus I've really heard more than once is The Devil's Steed, which must be one of the more stripped-down releases, and I think it rules.