What I usually do is look up a book on Amazon, and see what they have listed for "customers also bought".
Stephenson...Stephenson...Stephenson...moar Stephenson...Gibson -- meh, nowhere near as much fun to read, Pattern Recognition is his best, though (although I'm sure you're already familiar with)...Gaiman -- now Gaiman is as much fun to read, but he's much more fantasy than sci-fi, much less hard sci-fi. Check out Neverwhere if you've never read anything by him....yeah, good old stand-by's like Ender saga by Orson Scott Card, Dune by Frank Herbert...but again, the classic Stephenson sense of humor is missing. (Do you mind silly? Discworld is fun.) But they definitely satisfy the "good" and "hefty" criteria.
Christopher Moore is fun, but again -- more fantasy than sci-fi complete fantasy, no science fiction. And definitely errs on the side of sillier than Stephenson.
You know what I enjoyed? Slant, by Greg Bear. I'm sure there are other books by Greg Bear that are better, but Slant was my first.
...bunch of names I'm not recognizing...my friend is trying to get me into Richard K. Morgan, but he caught me at a bad time (I don't do a lot of reading these days)...my friend is into hard sci-fi...