Boards

but see if you can get hold of "The Black Album".

Also: Herbie Hancock - "Headhunters"

and it sort of depends on what you're calling classics - like, I assume you're listening to Parliament as well as Funkadelic, and stuff like Curtis/Marvin/Isaac/Otis/Aretha/Sly/Sam don't need covering? All sorts of Stax & Motown compilations as well, featuring stuff I'm sure you're familiar with (you can get the 3-disc sets Motown Chartbusters 1-3 and 4-6 at under a fiver a pop from Amazon if not - that's all 6cds for about £9 - can't go wrong).

This is a really, really good classic soul compilation you can pick up for a few pence secondhand http://www.amazon.co.uk/Platinum-Soul-Legends-Timeless-1957-1975/dp/B000078533/ref=sr_1_1?ie=UTF8&qid=1335900344&sr=8-1 - 3 discs of tunes that would be a bargain at ten times the price. Another brilliant triple-box (and one you should really hear as a Prince fan) is the new reissue of Shuggie Otis's three '70s classics - Freedom Flight and Inspiration/Information are still sublime.

Couple of other favourite albums (aside from the really obvious stuff like Hot Buttered Soul):
The Temptations - All Directions & Psychedelic Shack
The Isley Brothers - 3+3 & Go For Your Guns
Bootsy's Rubber Band - Ahh...The Name is Bootsy, Baby
Kool & the Gang - Spirit of the Boogie
Sly & the Family Stone - lots of people stop at Riot and Stand!, don't be one of them. Life and/or Fresh should come next.
v/a - Chess Divas - a great compilation of singers like Fontella Bass, Koko Taylor, Sugar Pie deSanto, Etta James, etc

None of those groups are in any way obscure, but particularly with the first two there's maybe a tendency to concentrate on their '60s Motown singles and sleep on their '70s psych albums, which is a bit like listening to the Impressions and never checking out Curtis' solo stuff. Kool & the Gang, too - I think people don't realise how good/diverse they were.

There are obviously tons of rarer & more unknown artists, but to be honest my advice would pretty much be to search Amazon/Spotify/whatever for "rare/heavy/forgotten soul/funk" etc and wade through the countless compilations to see what sounds good.

In terms of slightly more recent stuff, Daptone are obviously kings (get the Daptone Gold compilation, or just dive in with Charles Bradley /Sharon Jones /Lee Fields /Budos Band), but there's plenty of other stuff - Mayer Hawthorne springs to mind as someone with pretty major publicity, and also on Stones Throw you've got Connie Price & the Keystones, who do live funk with guest MCs. If you like synthy stuff, you should definitely definitely check out Dam-Funk and the Sa-Ra Creative Partners if you haven't already.

Oh yeah, and there was this classic thread: http://drownedinsound.com/community/boards/music/3955611 which has loads of good soul stuff though most of the links are probably broken. And there was a spotify playlist I made of 2011 stuff which had some stuff you might be interested in http://drownedinsound.com/community/boards/music/4309346#r6402592

and I haven't even mentioned James Brown yet, but all I'll say is Love Power Peace at l'Olympia is far and away a better live album than At the Apollo.

http://www.youtube.com/watch?v=te0tRpnIAGI&feature=fvwrel

and I hear music in the street by Unlimited Touch

http://www.youtube.com/watch?v=B-WCTAEmoSM

then bounce, rock, skate, roll by Vaughan Mason & Crew

http://www.youtube.com/watch?v=B-WCTAEmoSM

and finish with the Prince mix by Dam Funk

http://www.waxpoetics.com/blog/dj-mix/a-prince-mix-by-dam-funk

Already a huge Prince fan. I just didn't really know where to go from where I am.

DJ-set-style cuts from the era when funk was just starting to mutate into disco

get the recent 4-CD Tom Moulton mixes boxset. Moulton is THE DON.

http://www.amazon.co.uk/Philadelphia-International-Classics-Moulton-Remixes/dp/B006W33UC4/ref=sr_1_1?ie=UTF8&qid=1335915874&sr=8-1

for current stuff Daptone & Dap Kings are killing it at present with acts like Sharon Jones, Charles Bradley and Lee Fields. Also Truth & Soul Records and anything to do with Leon Michaels is worth looking into. His band El Michaels Affair are just excellent.

For older disco stuff there is tons of great labels, my fave being Prelude Records from New York. And similar to the prelude sound is Patrick Cowley and Bobby Orlando.

The Loft Classics are worth getting too;
http://www.discogs.com/label/Loft+Classics

And the Dave Mancuso Loft collections;
http://www.discogs.com/artist/David+Mancuso

Gil Scott Heron is also ace, try Moving Targat, Reflections- which has B-Movie on it which is his best track IMO, and Pieces Of A Man is may be his best known album.

Also this is just ace- http://www.discogs.com/Bill-Withers-Bill-Withers-Live-At-Carnegie-Hall/master/92871

Check out the comps on Trans Air
http://www.discogs.com/label/Trans+Air

Go through all of Gil Scott Heron's back catalogue. His era with The Midnight Band is arguably his richest.

For disco check out the John Morale M&M mix albums released on BBE an excellent label for all the genres you've mentioned.

As mentioned above for more modern stuff check out Daptone, Jazzman, Desco, Soulfire Record labels along with BBE which I said above.

Good call earlier about Sly Stones post Riot recordings in the 70s. The subsequent 3/4 albums are very good.

but there are also a lot of one-hit wonders & obscurities that you'll miss out on if you just focus on the famous names above. I first got into funk via various compilations, try & track down some of the following - should be able to pick them all up cheap on eBay:

Stone Cold Funk
All About Funk
Mastercuts Breaks
Sampled Breaks & Beats
Blaxploitation 1-4
Kurtis Blow Presents...The Breaks

Very true some of the greatest tunes were made by groups who scraped some cash together to record one 7' vinyl only to disband shortly after. Any compilation one the labels I mentioned above and Stones Throw will have more than enough classics like these to keep you happy.

Saturday Night Fish Fry has some great tracks especially.

Loads of offbeat bedroom soul and funk from the 70s and 80s. Some amazing tracks

http://www.youtube.com/user/Slayd5K

work your way through this guy's 700 or so videos

Awesome stuff

Slabs from the era when funk was just starting to mutate into disco, great stuff.

Also: The Last Days of Disco soundtrack.

....released this year is Escort's self titled album.

His run of albums from Hot Buttered Soul to the Shaft Soundtrack is superb.

Isaac Hayes has done some incredible albums. Don't think anyone's mentioned Roy Ayers yet another phenomenal artist.

I'd suggest (in addition to the above Youtube channel) Rick James, Zapp, Midnight Star, SOS Band, Chaka Khan etc

LOVE these
Mary Jane Girls - Candyman
http://www.youtube.com/watch?v=SqP-jI2vTsE

Nu Shooz - Make Your Mind Up
http://www.youtube.com/watch?v=WJavcikuCx0

Midnight Star - Midas Touch
http://www.youtube.com/watch?v=Hkp9f_CjEL4

Ready for the World - Oh Sheila (mini Prince Boy Band)
http://www.youtube.com/watch?v=wbL2lMn34Oo

Lisa Lisa and Cult Jam - I Wonder If I Take You Home (techno-pop RnB pioneers)
http://www.youtube.com/watch?v=UE4WokN5Z6s

Cameo - Back & Forth
http://www.youtube.com/watch?v=A2eU2CG3WN8

Zapp - Computer Love
http://www.youtube.com/watch?v=_bP48M2BEs0

And then there's some white electro funk
I'm a big Thomas Dolby fan, these are both from his Aliens ate my Buick LP. The first one is VERY Prince, the second one actually features George Clinton. Quality
Pulp Culture
http://www.youtube.com/watch?v=TdT4t0ywppA

May The Cube Be With You
gah, can't find either the LP or 12" version - here's a wrongly title radio edit
http://www.youtube.com/watch?v=gVPamd7UC5s

there's TONS more be these are the first that spring to mind

I'm sure Dam Funk has created a couple of compilations of 80's boogie funk stuff you might like. One's called Adolescent Funk I think.

I've got Pulp Fusions didn't recognise that breaks one on the link but have ones compiled by cutmaster swift and Mr thing. I'm assuming it's the same series. I'll check out the other one.

I'm sure Dam Funk has done a comp of tunes he listened to growing up that got him doing what he does possibly similar idea to shadows schoolhouse funk?

has some of the funkiest shit ever recorded.

http://drownedinsound.com/community/boards/music/3955611

sadly, many of the links no longer go anywhere but it still has some great stuff

...the Eccentric Soul series, brilliant stuff, oft forgotten and unheard

http://numerogroup.com/catalog.php?subcat=Soul-EccentricSoul

can listen to most of the albums here as well