Yes, the Cryptonomicon is great. I am the proud owner of a hardback first edition.
But its not his latest book. The latest book from Neal Stephenson is called "The Confusion"
http://www.amazon.com/exec/obidos/ASIN/0060523867/
And it is his second book since Cryptonomicon.
But Neals best book remains, to me at least, Snow Crash.