Oh god yes. I love her stuff even though it's directed for young adults. :cry:

As for books that I go back to again and again:

The Hitchhicker's Guide to the Galaxy series by Douglas Adams. Sci-fi, comedy and all around wonderful.

The Season of Passage by Christopher Pike. One of his horror adult novels, but one of my favorite books of all time, I'd say one of his best.

The Last Vampire series by Christopher Pike. For all you vampire lovers, it gets a little unbelievable in the last 2-3 books, but overall it is a strong series.

Anything by Neil Gaiman. The man is a genuis, pointe final.

The Green Mile series by Steven King. Not so much horror as a tale of humanity.

There are a few others, like The Giver, The Island of the Blue Dolphins and so on, but those are classics.