The Moviegoer question

For Cormac, my favorites are Blood Meridian and Suttree. Blood Meridian is rather dark but maybe the best book I have read. Certainly the books of the border trilogy are recommended if you are interested in the southwest. I could go on, because all his books are worth reading. The Road has a more contemporary theme if that appeals to you.
I strongly recommend the Moviegoer.

The Moviegoer, Message in a Bottle (essays), and Second Coming (which is a sequel of sorts to The Last Gentleman, so you'd want to read that too).

Full Disclosure: I have read quite a bit by Walker Percy, but I disliked most of it. I just don't like his style of writing fiction very much. I like most of his ideas, but I don't like how he expresses them in his fiction books.

I love his nonfiction writing. Lost in the Cosmos, in my opinion, is the book that best conveys Percy's usual themes. I'd actually recommend reading it first. Percy's books are all very based in philosophy, and I found that I like most of his books better after reading it. (I would really recommend going this route if you don't much care for Kierkegaard.) It's also the most painless discussion of semiotics that I've ever read.

I enjoyed Message in the Bottle, too, but it isn't as enjoyable of a read. Lost in the Cosmos is more stylistically cohesive, and it is funnier. I would pick up Message in a Bottle from a library for "The Delta Factor." That's the best essay in the book.

I'm on a run of Percy as well. Love in the Ruins is a modern Catholic masterpiece. While I prefer his fiction, Vanessa's right about Lost in the Cosmos: that's the place to start.

Lost In The Cosmos got me started. Then I read every one of his works of fiction. I hated to see the last one come to an end. I guess I'm recommending ALL.