I have a way of over-sympalizing things, so here's my attempt...
So Cal Style Reggae
Sublime, Slightly Stoopid, Pepper, Long Beach Dub Allstars (and shortbus), Too Rude, Mystic Roots, 311 (sort of), Expendables, OPM
Jamaican Reggae
Marley(s), Burning Spear, Buju Banton, Sizzla, Capelton, Junior Kelly, Gregory Isaacs, Michael Franti & Spearhead (definetely up-and-coming), Half Pint, Cocoa Tea
Matisyahu is amazing to, but I don't know where I would put him. I know not all the bands are So-Cal of Jamaican, but I classified them by using Sublime as the appitamy of So-Cal reggae/ska/punk/whatever, and then compared it to Marley, then I just put all the other bands in based on who I thought they were more similar to. Every band on the list I think is excellent.
BTW, Putamayo is a world music record label and they do world music compilations, I have Reggae Around the World, Latin Reggae and I think another reggae compilation, but they're excellent!
New Amon Amarth song available, check out their myspace!