Since my first attempt at a hell was deemed "too pedestrian," I have gone back, now that I have a little time, and been more creative. Caveat: this does not mean I have been more serious about it. It's still a joke. As stated in comments, I don't believe in a hell, so it's pretty pointless to take any of this seriously. Pet peeves abound, most of them petty.

Parents who bring squalling brats to R-rated movies
Circle I Limbo

Democrats
Circle II Whirling in a Dark & Stormy Wind

The Pretentious, Hipsters
Circle III Mud, Rain, Cold, Hail & Snow

Bill Clinton
Circle IV Rolling Weights

Republicans
Circle V Stuck in Mud, Mangled

River Styx

drivers who swerve through heavy traffic
Circle VI Buried for Eternity

River Phlegyas

People who believe everything they hear
Circle VII Burning Sands

George Bush
Circle IIX Immersed in Excrement

People who jet-ski too close to shore and scare the turtles
Circle IX Frozen in Ice

Design your own hell