Car time-wasting 1-4-04

As an interesting exercise, while driving home from Chicago the other day, I attempted to name a science fiction author who books I like and actually own starting with every letter of the alphabet.

Despite doing this from memory, I got every letter except I, Q, U, V, and X. I will be examining my bookshelf later. Any obvious ones I'm missing, other than Vernor Vinge, who I haven't actually read?