Personally, I was incredibly upset when CompUSA closed, but that closure made me psychologically stronger. 
Amazon. It’s absolutely stupid how much money I spend there. Plus it’s my connection to books in a town with few good book stores.
CompUSA is back in our area, they use that name for the former Tiger Direct store. They sell lots of PC parts along with PCs and TVs.
They have 30 stores now
Apple.
Adobe.
Google.
This is a poll, so I’m moving it to IMHO.
twickster, Cafe Society moderator
The one I work for.
Otherwise, in terms of providing a service I couldn’t easily replace to my satisfaction: Netflix.
Google
Amazon
Creative Loafing…or whoever it is that keeps this board functioning these days.
(And I hope I’m not the only one. )
I’ve been on a ton of boards over the years, but yes, this (SD) is the only one I’ve felt “at home.”
IBM (not just because I work there)
My local comic shop. That would suck.
My favorite radio station just got sold and turned into some top 40 crap. That left a much bigger hole in my heart than I expected.
WalMart
The one I work for, of course.
Beyond that, one of our competitors, which would drive a chain of supplier bankruptcies that would affect my business.
Whataburger
Oo, yeah. A couple years ago or so, there was this local hard rock station that I loved. One day at noon, with no apparent fanfare, the format turned to oldies - sock-hop music, etc., not classic rock or anything. I listened and eventually heard the new call letters, and realized they’d just changed formats. In retrospect, I suspect it was intentional that the last song before the changeover was Metallica’s “For Whom the Bell Tolls.”
Other than Amazon, I’d say Northern Brewer (my main homebrew supplier), and oddly enough, the corporation that owns Old Navy, Gap, and Banana Republic. I have a long pants inseam and can’t buy pants off the rack at nearly any department store, but these stores have long-inseam pants on the rack at the latter two stores, and long-inseam jeans at the Gap/Old Navy. (Haven’t checked Banana Republic.) I can also get them online from those stores. Finding more-or-less reasonably priced pants and jeans that fit me in shape and length is such a hassle, and I’ve given up on not-quite-long-enough hemlines while wearing flats, never mind what happens if I want to wear heels. These stores are conveniently located for me, and have good prices - or good sales at least - plus (barring Old Navy) they’re not way too young in demographics for me. I’m skimming along the edge of “too old” for Old Navy but their jeans fit great.
I’ll second Adobe.
Also, Chick-Fil-A. They’re really the only relatively healthy fast food joint, they take care of their employees, and they put their values over money, even if I don’t agree with those values.
I agree with Amazon.
Eh, that company…I could take it or leave it 