Before I set up shop, I order from Netrition, then I moved to BB.com.
If I was ordering products today and didn't run a business, I would problably go with Bulk Nutrition due to the wider range of speciality products and service.
My business (
www.caliberfitness.com) mainly focuses on low cost classic bodybuilding supplements such as Milk & Egg Protein, Liver Tablets, Amino Caps, etc however I did recently start selling products for Synthetek Industries and brought in some newer products
It really depends on the products you like and how you train.