I haven't read a ton of his stuff, but Schrodinger's Cat and The Illuminatus! Trilogy had a profound affect on me when I read them in high school.
It was through him that I found out about Discordianism. And even though it's a joke dressed up as a religion (or vice versa), it's still drastically influenced my life in not-so-subtle ways...
*getting involved in the Knightood of BUh
*embracing the tenants of improv
*accepting that we create our own reality, and enjoying that.
That's part of how and why No Pants Day became a success. It became real because we said it was real, and the force of our conviction made it so.
Anyhow, R.A.W. was a cool dude.