Good point with the revolution. A lot of people in our generation can't grasp an idea of having to 'fight' for what they need, deserve or whatever other reason they might have. Most people nowadays say 'hey, everything's always given to me so why should i fight' [thats if you're an average american who doesn't deal with day to day violence and oppression].
The movie fight club actually brings up that point. We really are the middle children of history. We have no great struggle, no great depression. Our great depression is our lives.
That always inspired me. Where is my life going? Would my life story be a good book? I think thats really a driving force behind my want to do things out the ordinary. Certainly, fighting in a war isn't something you should go out and do just because you want to tell stories when you're older. I'd find it to be a spiritual connection to every other soldier throughout mankind's history. Its like if you fight, you get to experience that same return to animal instincts as your comrad in the foxhole next to you.
That brings up my next reason to fight. Where else will you find true human emotion in as rare a form as during a firefight. Brothers fighting in arms will and against each other, saving lives, ruining others, making desicions that would have you going home in a box, or your sargent lying face down in the chaotic front lines. Most won't experience that kind of life changing experience, but if you do, you possess a kind of wisdom, because you've had life put in perspective in such an intense way, that there's no way you won't be changed, forever.
Essentially, war sucks for everyone, but for those see past the violence and bloodshed, war is just the world working itself out. War doesn't always have to happen, and many times it does when it shouldn't, like WWI for instance. But other times, its the everyone's collective duty to stand up for whats right and just for mankind and thats a war i'd want to fight in.