Ok Commodores I dont have any albums, but you want the early stuff, cause they kinda sell out with crap like Three Times a Lady later on..
Gonna Blow Your Mind and Machine Gun are great tracks, and are both on the album Machine Gun but I dont know any of the other songs from it so I am sorta adverse to actually recommending it..
Parliament have a lot of good albums. They are all concept albums about how Starchild travels through space battling Sir Nose D'Voidoffunk and delivering funk to the needy..
I think Funkentelechy Vs. the Placebo Syndrome is my favourite,
but the Mothership Connection is probably a better starting point..
Some highlight tracks from other albums are: Testify, All Your Goodies Are Gone and Rumpofsteelskin.
Funkadelic on the other hand have not as good albums but probably better songs overall. My favourite albums are Lets Take It to the Stage and One Nation under a Groove. The Cosmic Slop, Cholly, Better by the Pound, Music for My Mother are my favourite tracks..
James Brown there is so much, and all of it is great because it is all kinda similar I guess (at least more similar than like Parliament or Funkadelic at any rate). The tracks of his I have 5 starred are: Super Bad, Get Up (I Feel Like Being a) Sex Machine, Doing It to Death. The only album of his I have is Star Time, which is the only album you need (its a 4 cd set). So I cant really recommend anything other than that.
Have a nice day.