Here's a "smoking" mix I made awhile ago, it kicks serious ass. Includes rap, rock, reggae, and even classical.
1) E-40 - Broccoli
2) Mac Dre - I Need an Eighth
3) Bone Thugs n Harmony - Ecstasy
4) Pink Floyd - Hey You
5) Jimi Hendrix - Purple Haze
6) Song from the movie "Half Baked" when they pull out Billy Bong Thorton. It's reggae.
7) War - Lowrider
8) Bone Thugs n Harmony - Buddah Lovaz
9) Tchaikovsky - Dance of the Sugar Plum Fairies
10) Dr. Dre - Light Speed
11) Snoop Dogg - Tha Shiznit
12) The Red Hot Chili Peppers - The Zephyr Song
13) Bone Thugs n Harmony - Weed Song
14) The Flaming Lips - It's Summertime <--Good smoking band, also check out Yoshimi Battles the Pink Robots and Fight Test
15) Pink Floyd - Good Bye Blue Skies
16) Sublime - The Bong Song
17) Incubus - Aqueous Transmission