I think I've read all his books. But his work is pretty diverse, so you get to pick and choose based on taste and preference.

There was a time when I thought Snow Crash was the best. There was a time when Cryptonomicon was a lot of fun (still is). Nowadays I incline slightly more towards the 'philosophical opus' type of vibe that Anathem gives off.

Anyway, all his books are pretty good representatives of one sub-genre or another. He's a very good author, and he wrote in a lot of different keys through his career so far.