Decisions decisions

In case you haven't noticed running has become a bit more than a hobby. I tend to have an addictive/obsessive personality, which is why I don't drink, smoke or have any real vices. I'm afraid that they'll become addictions. Running has sort of turned into that. And while I'm careful to make sure it doesn't take over my life or become a true addiction it does sort of trump other activities at times.
Take my current dilemma. There is this play that Conexion wrote about last year. I've stayed in touch with the show's creator as she's tried to bring the production to San Antonio. Well it's finally coming. The only problem is that it's coming the day before the half marathon I was hoping to run in Dallas. So now i have to choose: the play or the run.
Part of me feels like I should do every run I can, because who knows how long I'll really be able to do these sort of races. Eventually life gets hectic and a marathon and 4 half marathons in a year is not reasonable. Heck, a single marathon and the time commitment it requires might not be at all an option in coming years. So I can't figure out what to do.
Usually I make decisions based on: someday am I going to look back and think "I should have done that instead of that."
Unfortunately this isn't one of those decisions that is that easy to make for some reason.
So now I'll sit and ponder this until after the Marine Corps Marathon, which is when I'll make all my plans for the remainder of the race season. In the meantime if anyone has any opinions on this, feel free to share :)