If you're into afrobeat, i'd suggest antibalas, nomo, kokono no. 9, budos band, mr. something something, and afrodizz.
Not to sound like a "purist", but these guys are pretty much all "imitators" who are limited to the Fela formula (which, as far as bass is concerned, is one of the easiest styles to pick up if you're used to playing funk). The Congolese suggestions are great. There is a specific bass playing style associated with, for example, Congolese rhumba or soukous, whereby the bassist uses his thumb and fingers in a guitar-picking manner. You just can't get the same effect using just fingers, thumb or a pick. Find some footage of Kanda Bongo Man (a definite favourite!), Diblo Dibala, Zaïko Langa Langa or Franco and you'll see what I'm talking about. I spoke to a bassist from Cameroon once who told me that the role of the bass player in a lot of Cameroonian stuff is to effectively play drum parts. The thumb, for example, would play a low drum pattern while the fingers would play a higher-pitched drum pattern. There is a huge range of music on the African continent and it can be daunting trying to figure out what's what and where to start. I would suggest picking up Jean-Luc Ponty's "Tchokola" album for two reasons: the players are killers who really know their stuff and each song is based on a particular rhythm which is discussed in the liner notes. Of course, you'll have to put up with the violin, but...
Otherwise, I'll add these names to the already good list:
Les Têtes Brulées (some pretty crazy stuff from Cameroon that can be quite complex rhythmically).
Salif Keita (check out the albums "Soro" and "Folon... The Past").
Anything by Kanda Bongo Man, Zaïko Langa Langa or Franco.
Pretty much anything by The Soul Brothers (township jive from South Africa) except for their remix album!
Anything by Sweet Talks (the album "Hollywood Highlife Party" is a classic).
There are tons of compilations out there to help you discover the music of Africa. Anything on the Stern's label should steer you in the right direction.
I'd also suggest you check out Kassav'. They're not African (most of the members are from Guadelupe), but their style would probably fit into the kind of vibe you seem to be interested in (and, really, any musician should be aware of this band - they're one of the best out there). Check out their-single disc "Live Au Zenith" album.
