"Cannery Row" is the only work of his I ever read, but it amazed me. One of the best books I ever read. I love it. Just beautiful -- the easiness of American writing combined with deep feelings and weird characters ... just one of the best books I ever read. Can't quite point my finger on it, but it was.
I've read Of Mice and Men, The Pearl, and Cannery Row. The Pearl was passable, I didn't like the writing style; same could be said about Of Mice and Men.
I liked Cannery Row a lot. I tried to read East of Eden (got about 200 pages in), and Steinbeck simply can't write plot worth a damn. Cannery Row is really without plot, and more of an exploration, and is quite vivid and enjoyable. It seems weird that the best book he's ever written is rather unorthodox, as opposed to all his other works, which are Great American Novel form and bland.