Hmmm...  Yea olde rubbers...

What type is the best (to load up on if a provider)?  I mean this for both providers and hobbyists- which one feels best for both, good fitting, all of that.  Let's say a provider needs to stock up - what should she be looking for on the store shelf...  And I mean brand, type, and if they have different sizes, what are the ratios (20% medium, 60% large, 20% extra large) to stock up on...?