There are a bunch of good seed banks. Herbies and Attitude are great choices as a default bank, but they don't have everything either, so you will likely want to look elsewhere from time to time.
Herbies - General Orders - (favorite, heavyweight fruit punch, not available on attitude)
Attituded - General Orders
RCMC - Northern Outdoor + a few exceptional indoor strains (favorite HighRise c99, very very interested in HighRise MOB and HighRise Fire99, next order)
PeakSeedsBC - Northern Outdoor + quality source for some older strains. (Northern Lights, ...)
Happy hunting, and remember take criticism of seed companies with a grain of salt, worry more about the specific brand and strain reviews/reports/journals, not just brand bitching. There are bad examples of Nirvana and Greenhouse Seeds, but there are also a few great ones... I say screw brand loyalty entirely.