Military flying (FJ) is fantastic and for a young guy cant be beaten IMHO. But there is always the lure of money with the airlines.
Depends what your after I suppose.
Dont join the mil and hope for stable lifestyle, lots of money etc. But then dont join the airlines if you want to fly low level v quick, drop ordanance and see the bits of the world that generally dont have international airports that welcome you in a friendly manner.
Have fun no matter what you are lucky enough to fly though, it all rules!