I'm gonna take a crack at the most obvious

7 Queen (with pink d!ld*s)
8 Gorillaz (Can't miss em)
9 Led Zeppelin (That blimp is clearly ledish gray)
10 Scissor sisters (The pink scissors below the hammer man who is...)
11 Smashing Pumpins
12 Guns 'n Roses (on the chart behind the Queen)
13 Eagles (to the center right)
14 Pixies (above the zombie=
15 Madonna (painting in window right of zombie)
16 Prince (getting mugged by the queen)
17 Matchbox 20 (behind the prince)
18 Eminem (well atleast some m and m's)
19 Eels (between queen and prince)
20 Black Flag (right building in the background, above boulder)

(This is a great thread Chris, thanks )