For hose clamps the best that I've found thus far is "ABA" brand and the most reliable place that I've found to get them is West Marine. These are the type with no holes in the band for the rubber to extrude through.
The absolute best hose clamps are the Mubea spring clamps. They come in different diameters for all applications, fuel to radiator hoses.
They are "constant tension" clamp vs. a "constant diameter" clamp. Spring clamps are constant tension and provide the best sealing. They sell to the OEM companies.