In no particular order some of the biggest breeders in the biz that have great reputations. There are also many small scale breeders that are great people and have amazing animals but the BOI should point you to those.

Ralph Davis Reptiles (www.ralphdavisreptiles.com)
VPI (www.vpi.com)
NERD (www.newenglandreptile.com)
Peter Kahl Reptiles (www.pkreptiles.com)
Bob Clark (www.bobclark.com)
The Snake Keeper (www.ballpython.com)
BHB (Brian and Lori)
Reptile Industries (Mark and Kim Bell)
Greg Graziani (www.grazianireptiles.com)
8BallPythons (www.8ballpythons.com) aka Adam_Wysocki

And a few others I've used
Garrick DeMeyer (www.crestedgecko.com)
Camlon Reptiles (www.camlonreptiles.com)
Eden Snakes (www.edensnakes.com)
Jim Stelpflug @ SW WI Reptiles (www.swreptile.com)
Michael Cole (www.ballroompythonssouth.com)

There a ton of other great breeders out there, many of them members of this site...so don't pass them by!

-Jason