Not to sound like a broken record, but I definitely gotta go with what most people said above.
Nothing pleases me more than to walk into a shop that has that one hard-to-find thing that it seems everybody knows about and wants, but nobody sells.
Also it's frustrating to ask a shop about something and their reply is always "We can order that." That's an OK answer for less common requests, but when that's the answer for more common things (i.e. they don't stock anything, really), it just makes me not want to shop there. Not to mention when told their price it's $40 more than what I can get online, AND I have to pay shipping. Let's see.....$40 less plus free shipping online......I'll order online.
I think one of the keys to success is to supply enough to keep the DIYers satisfied and also to take care of the peeps who don't want to, or can't, do it themselves.....while maintaining profitability from both groups.
Sounds easy, doesn't it?
b