Terry Pratchett is probably the funniest writer
I have ever read, with the possible exception of Dave Barry when he is at
his best. The Discworld Saga is mostly great (as evinced by its enormous
popularity), with a few minor potholes in the road, and a few glowing stars
as well. The best, I think, are Reaper Man and Small Gods.
I will endeavor to get the full list on this page, in approximately chronological
order.