
Out of several (expensive) books I do have, these are the ones that've been most helpful:
- Verilog HDL Synthesis by Bhasker - FPGA Prototyping by Verilog Examples by Pong P. Chu - Advanced FPGA Design by Kilts - The two "Learning By Example using Verilog" books by Richard Haskell (these are actually written specifically for use with the Digilent Nexys2 board I mentioned in an earlier post)
Many of the others are impractical, academic junk that waste your time with things like gate-level design, Karnaugh maps and the like that are handled by the synthesis tool nowadays. Unless you are writing a synthesis tool you don't need 75% of what's in most HDL textbooks.
Chandra Thimmannagari's CPU Design has a chapter on Verilog with many instructive short but nontrivial examples, in a novel compact format.