I was going to post in here seriously, until I realised they way it was going, but I've always been a firm believer that you should support the club that you grew up around, or whichever feels most "local" to you.
I realise there are plenty of people with pretty random supports, and that's fair enough, but it's always been part and parcel of identity to me. I'm a Londoner, thus I like Arsenal. I follow Hull City because I "get" the City of Hull nowadays. Any kids I ever have (god help them), would support a team near where I raise them.
Horses for courses though I 'spose.
I understand your point, but I was brought up by a Man Utd supporting dad in a Glasgow Rangers supporting family (majority of my family are Scottish, including my mother), but at such a young age Manchester could have been closer to where I lived than Middlesbrough was. Geography wasn't a strong point at 4 years old, so it's a bit of a none-starter in that respect.
As much as I dislike most Middlesbrough fans, I do follow their results week in and know more about their squad than most people I know who 'follow' them because I have 2 friends who are absolutely crazy about them and we talk all the time (as a result, they follow Man Utd and hope we do well).
I do, as many of you know, get to Old Trafford, although financially this season I've only been able to make one game which sucked and have actually turned down a ridiculous number of matches, including yesterdays.
Football is so much more a World game now than it was years ago, teams are reachable in so many ways and it's easy to feel a part of that club from anywhere due to TV, Club channels, websites, sports news being so readily available. In the past being local really was required to truly be a part of the identity of a club, picking up club programs and learning new stuff every home game, but these things have been voided by the access to watching your team live on TV, following post match comments through websites (or if you're an Arenal, Celtic, Man Utd, Chelsea, Liverpool fan, through their TV channel), on Match of the Day, watching on the Internet and of course, conversing with other fans on Sports forums such as this one.
Football is no longer a local sport and some people don't want to acknowledge this.