Marathon: the quintessential running experience?

It's that time of year again--the annual crisis of my running conscience. Registration for the 2010 Houston Marathon came and went in about 48 hours. And while the bike cops at Memorial Park ticket the illegally parked Houston-Fitters, and the blackberry buzzes with fundraising solicitations from registered friends, the nagging thoughts resurface: can I really call myself a runner if I don't run marathons?

It's not about the distance. I've completed longer - 50K's (slowly). It's more about the experience. The thousands of other runners. The loads of spectators. The bands playing in Memorial Park. The not having to give a primer on the metric system. The having that easily communicable, universally-understood, 3 digit classifier of athleticism -- the marathon finish time.

It's also about the walking. Trail race terrain can be technical, and the race distance is usually sufficient to justify some walking. At least in my experience, walking inevitably happens before mile 26. On the other hand, a flat, fast marathon like Houston is run -- without walking - by elite runners and weekend warriors alike every year.

So, cue the nagging. From the little voice that says "but there was walking involved" whenever someone commends running longer than 26.2...and says "but this would be a lackluster marathon finish time" (the 5 extra miles, soul-sucking sand, and curse-inducing roots notwithstanding).

And there's the rub. I detest running on concrete (almost as much as I detest loops) about as much as I revere the tranquility of single track in the woods. The thought of paying good money to pound away on pavement, on city roads I can run anytime, with a few thousand too many other runners, is enough to make my quads cramp.....but am I missing out on the quintessential runner's experience....is the marathon (or half) the universal language--or the secret club code--of "true runners"?