Pinataland: Odd, alternate-historical music. Including violins, tuba, accordion, guitar, OLD music samples (Edison cylinder old) and even theremin.
Finntroll:Finnish black metal. Ever wonder if accordion could enhance black metal? These guys pull it off.
Mephiskapheles: Satanic ska. Makes me wonder if somewhere out there is a satanic country band.
Symphony X: Heavy, yet more musically interesting than most metal bands.
Shelleyan Orphan : Jazzy Indie-pop, with cellos!
Honolulu Mountain Daffodils : The greatest unknown band ever -lead singer commits suicide in Tube station!
Southern Culture on the Skids: Campy country-fried rockabilly with a little surf guitar thrown in for good measure.
Pink Martini: Alternatingly fun and sensual jazzy classical songs sung in various languages.
I like Finntroll as well. Most of the bands I like are obscure, I suppose.
Sir, I introduce you to Slightly Satanic and also The Coffinshakers. (OK, so Coffinshakers are more “vampiric” than “Satanic” but some of their songs are close enough.)
You don’t see too many Finntroll fans out there. It’s a shame–they really do fantastic stuff, and it’s worth having one of their albums if you ever need to clear a party or make a point to neighbors who are too loud.
Sacreligeum: Dang. Too bad they put music up on mp3.com (which has recently taken a dive directly into the toilet). Same problem with The Laziest Men on Mars.
Now for some interesting obscure cover bands.
Minibosses: NES music on guitar. Good stuff.
Lounge Against The Machine: Saw these guys on Later with Carson Daly. While I do wish they had continued running SCTV instead of Carson Daly, LATM was pretty good. Closer by Nine Inch Nails done lounge-style? Count me in!
Apocalyptica: German band does classical heavy-metal style, and vice versa. They did an absolutely killer version of Grieg’s Hall of the Mountain King.
You know, over the years I’ve had a few albums that I just keep buying over and over. When I lose them…I’ll find another copy. The hardest for me to find when this happens is ‘Catholic Boy’ by the Jim Carroll Band. I think I’m the only one that listens to that album. It’s been around forever!
I loved “Catholic Boy.” “All the people who died, died!” 
Sticking with current acts:
The McKrells – Celtic bluegrass. Really. And they make it work.
Otis Taylor – Superb blues musician with a dark, hypnotic style.
Deborah Coleman – blues guitarist. Fine singer, too.
Going further back (I’ll just list – I’ve talked about them enough on this board):
Kak
Emitt Rhodes
Bonzo Dog Band
McDonald and Giles
Flash and the Pan
David Grisham
Not really obscure in their time, but it looks like The Band is pretty much forgotten these days.
GAH!
The Band has given me a PSTS for being trapped in someone’s house being forced to watch this peice of crap video. I’d probably me more receptive to it now, years later, but then, it was pure torture.
Annie Capps Not only do I like her and her husbands work, they sang at our wedding.
Sharon Shannon one of my favorite accordianist evar! Accordians rock.
That would be PTSD.
Johnny Connolly for more accordian music. You know you want it.
This may not be obscure enough for this thread:
Jim Carroll isn’t exactly obscure. since many folks know about “People who died” as well as Basketbal Diaries.
However, for fun with Jim Carroll and obscure bands you can alway pick up a copy of Put Your Tongue to The Rail which is one fo the best cover albums…ever. Lot’s of obscure bands there (Catholic Boy is done by a band called Bottom), including my favorite obscure band Burn Witch Burn.
The Soft Boys, although they’re probably fairly well known on the SDMB. Loud guitars, three/four part harmonies lyrics with many references to seafood, what’s not to like? Recently (relatively) reunited for a new CD They have a web site here
My other choices are history:
Doll by Doll. c’mon has anyone here heard of them? First three albums were brilliant stuff.
The Waitresses I don’t know how well known they are, someone’s done a website here
The Bonzo Dog Do-Dah Band Already mentioned by RealityChuck
“This album would have sold a lot of copies, but the people who were going to buy it – they died, died!”
Half Man Half Biscuit (check out their Back in the DHSS album)
**The House of Love ** - two hit wonders but stood the test of time for me.
The Pixies - only obsure in the UK of course.
There is a whole slew of bands from back in the day that I hope someone with no profit motive whatsoever will want to release on CD one day:
Folk Devils
World Domination Enterprises
Inca Babies
Rubella Ballet
Primevals
Iguana Foundation
Underneath What
Bambi Slam
Basti
To mention a few.
And NQK, Pixies were huge in the UK before the rest of the world even took notice and calling House of Love obscure is pushing it a bit.
I guess that these bands are maybe obscure enough to fit in here.
Godspeed You! Black Emperor
A Silver Mt. Zion (Or, I guess, to be technically correct The Silver Mt. Zion Memorial Orchestra and Tra-la-la Band)
…and just about everything on Constellation Records. I saw ASMZ in London recently. Fantastic!
And at that concert the pre-band was called Ella Guru. They haven’t even released a full album yet, so I doubt anyone here has heard of them. Their single is fantastic. Check it out at their website. I can’t wait for their album to be released.
My brothers band, The Peoples Front
Check them out.
You beat me.
Hank Williams III and the Damn Band.
Donna the Buffalo
Cheat
Me, Mom & Morgentaler - band from Edmonton, Alberta. They used pretty much every instrument known to man, had songs in english, french and spanish and had a wonderful tune “Anarchie” (anarchy, en francais)
I’ve been looking for their cd for years.