I believe so, and @creative1 is a prime example. In fact, I notice it most when it comes to Apple in general (iPhone, iMac, iPod, iCaramba!), though it’s also pretty strong amongst Ford and GM owners who would rather buy a car made in Canada or Mexico that has their logo of choice on it than a Toyota or Honda that was built here in the US. Somehow, it’s more American?!
Personally, I am usually brand-neutral, though I admit that I prefer buying from companies that make good, reliable products that are a good value for the money (which is why I drive a Toyota and will probably never buy an Apple product). I generally let my buying decisions be based on technical merit and the company’s reputation.
For instance, SanDisk makes good stuff and the old e280 blew the older iPod Nano (the only other MP3 player that was even close at the time) out of the water at half the price, so I went with the better, cheaper, more reliable product. I also trust their USB Flash drives after having one sit in a snowbank (and later, the resulting mud puddle) for a couple of months and surviving a few trips through the laundry without losing a byte. However, as much as I like and trust SanDisk, I will consider other brands if they offer the same quality. Hell, I was given an iPod Touch that died within a 18 months while my six-year-old e280 is still rocking. I thought it was an upgrade, but the ability to run apps pales in comparison to the ability to power up at all.
Many people are loyal to Microsoft and refuse to try alternatives like Linux or even a non-IE browser like Firefox for no reason that makes sense to me other than brand loyalty. I have also noticed similar behavior amongst cooks/chefs when it comes to their equipment. Same with mechanics who only buy one brand of tool.
At the end of the day though, it’s often more about advertising or basking in past glory than about merit. Many rely on either their reputation or some brainwashing to drum up business and don’t care about what sort of crap they are actually selling as long as the profit margins are fat.