The Chip Rack is an anuually updated guide of all Nevada chips. All kinds, all denominations.
The Official U.S. Guide includes all chips from legal casinos in the U.S. except Indian Reservation and Puerto Rico.
Greg Susong publishes a guide for Riverboat casino chips.
Ralph Pollack publishes a guide on Dutch Caribbean casino chips.
Archie Black publishes a guide for Atlantic City casino chips.
Archie Black and Al Rollins each published a guide on Puerto Rico chips.
Alan Banick publishes an annual Colorado Chip price guide.

If I had to pick only one guide, it would be the Official Guide. It covers more territory than any other guide. But all the guides are excellent. I own all of them and get all the annual updates. Support the authors if you want the hobby to prosper.