I am ex-RAF and feel a sense of caution as I read some of the replies. As one who does not always agree with Rainboe, I have to say that his is the most useful advice here, followed by that of Wingswinger. Many RAF guys have foolishly believed that they are better than their civilian counterparts. That is not my experience personally, and a handful of misguided and inappropriately arrogant ex-RAF pilots have done a great deal of damage to the reputation of Service pilots. A previous poster said that you are paid twice as much for a job that is half as difficult - I am afraid that attitude will lead you to serious problems in the airline world. My own experience is that, just like the RAF, most days are very routine but every now and then it all gets very tricky.
I think the best advice that you can get is to get rid of your white gloves, never ever talk about how much better it was in the RAF and be humble enough to learn from people who actually do know quite a lot about flying themselves. If you have that attitude you will have a great time. The final bit of advice I would give is not to write off low cost. The only people who do are those that do not work there. I love the low cost world - it is a great job with loads of variety and I get home most nights. Personally I would have hated to work for BA but I recognise that many people have really enjoyed it. I can only speak for easyJet but we are professional to the core and in the challenging times ahead you could do a whole lot worse. Best of luck.