I think Fish Aquariums and Stuff on Fairview Ave in Boise is very good. I have had very good success with their fish even though I live 100+ miles from there. They do have a limited plant selection but everything I purchased from them has thrived with one exception where I chose a plant requiring more light than my low tech aquarium provides..
Boise Freshwater Aquarium on Overland has a broader selection of particularly cichlids and is visually more impressive with some of their huge tanks. Their plant selection is also fairly limited and I have not purchased plants from them.