Well let's see...

*Getting elite status and a better chance at perks (better seating, upgrades, more respect from airline employees.)
*Nice shiney gold and black and other cards.
*The chance to gloat at dinner parties "Well I'm PRemEx on United, Platnium on Starwood, Gold with Hilton and Marriott" and have people stare in awe
*And the BEST reason: A FlyerTalk get together or two or three halfway around the country (or the world) requiring a BIG Mileage run.

But having these Flyertalk get togethers are a great way to be in the chase and have a fun time with the greatest travelers in real and cyberspace!

And make a few friends along the way! That's the great award of the pursuit of Miles! The pursuit of happiness with friends (That's my main mileage run goal!