Music I love to smoke to would be Southern Rap, screwed & chopped. Especially with couchlock bud you just chill with, the slow beats just take you away to a land where you can just relax and chill.
artists include:

Big Moe
Big Hawk
Fat Pat
Trae
Z-Ro
DJ Screw
Lil' Flip
Lil' Keke
South Park Mexican
Juan Gotti
Shy One
Three Six Mafia
among others.

other artists I like to listen to, but that aren't Screwed & Chopped, include Bone Thugs' N' Harmony, 2Pac, some Notorious B.I.G., Luniz, Snoop Dogg, and again, others.

Favorite Songs:

I got Five on it - Luniz
I'd rather bang Screw - with Big Hawk and the Screwed Up Click
Boss' Life - Snoop Dogg
No More Pain - Z-ro
Gotta be a G - Z-Ro & Trae
No Help - Trae ft. Z-Ro
I go through so much - Z-Ro
Speak on it - Z-Ro

those songs, slowed down, while I'm really high, really really relaxes me. I could have had the worst day, someone could have died, I could be terribly sick. After a nice, fat blunt of some good weed, or a few good bowls through my glass goddess, and with those songs on... Man, it's like nothing matters. Nice to refresh your perspective every once in awhile.