Peterson's guides have been a mainstay for birders since his first publication in 1934.
Revised in 2010 with updated text, paintings and range maps, Birds of Eastern & Central North America covers 500 species (sixth edition, 2010, 464 pages). Birds of Western North America covers 600 species found in areas west of the 100th meridian and north of Mexico - essentially areas in Mountain or Pacific time zones (fourth edition, 2010, 500 pages). These two classic field guides are a compact 5" x 8" size.
Also available is the 2008 edition of Peterson Field Guide to Birds of North America, which is a compilation of species in the eastern/central and western regions (544 pages, 6" x 9").
All three books have Smyth-sewn, flexible-back bindings with vinyl covers. They include a website link to access video podcasts that supplement the books.