Lovely post, Ingrid. I, too, try to buy locally when stock is available and when the price difference isn't too great.
I believe in having access to both good local service and the price benefits of large volume buying power. What usually happens, then, is that I shop for price and availability locally at our larger distinctively local stores (I try to avoid the chains) and compare with my favorite on-line dealer. If both have stock, I'll buy locally if the price difference (including shipping from NY) is less than our state sales tax and figure it's worth paying a bit more to have the goodies promptly and pre-inspected. If the on-line store gives a large enough price break on the more costly items, then I order on-line, wait a few days (impatiently, what else?) and hope everything arrives intact.
So, usually, the local stores get my business for most accessories and some bigger-ticket purchases. The on-line retailer sells me discounted camera bodies, most lenses, and stuff that isn't in stock locally. Both types of retailer help me get what I need, and I'm happy to help both types stay in business.