Choxy,
If you spend much time on this site, you'll find rickair's advice to be quite good. I'm not going to disagree that AD isn't about some of the things he describes in his post but I will say that it isn't always that way. I'm at 26 years of service and have flown the whole time. However, if rising through the ranks is a goal of yours, don't do as I have done. Lt Col is about as far as you'll get. That being said, I wouldn't trade my career for a 4 star general's!
Cheers,
Jethro