I know I'm reviving an old thread here, but I've been giving some thought to this. First, I do believe that anything you do your whole life you will want to not be doing during your time off. That doesn't mean you shouldn't find a career that you find enjoyment from, just don't expect to be paid to go hiking. You have to think hard what it is about the outdoors that you like. It is the break from your regular life and a chance to refresh? If so, making a living in the outdoors may remove some of the charm.
If it is simply a loathing for being in a cubilce and wanting the sun on your back, there are plenty of 'outdoor' blue collar jobs, and I know many people who enjoy this type of work. But it won't be a wilderness experience. For example, you could become a surveyor, but you may spend much of the time by the side of busy roads. You can become an arborist or landscaper, but you are 'domesticating' the landscape. If what you like about the outdoors is the sense of wild, this may not be satisfying either.
And of course, would you like to come home to a spouse and children everyday, taking them to the mountains on the weekends, of would you prefer to be holed up in a lookout tower for weeks, while missing your kid's soccer games, etc.
It seems there are two types of careers; those that pay well because they require a great deal of responsibility (read: extra hours), and those that afford a moderate lifestyle, but that you get to clock out of. So, for example, I am a musician, and so I work many nights and weekends. Even though I love music, and many people dream to have my job (I am an orchestral conductor), I have come to resent how often I cannot get out into nature on the weekends.
There are many jobs that pay decently, have flexible hours, and you can 'clock out,' taking your mind off work. For example, I know several nurses, both men and women, who love their jobs, because they work three 12-hour shifts a week. They can schedule 4 day weekends if they want, or take a mid-week hike when the trails are empty. It is much harder to do that the higher you go up the career ladder and your responsibilities increase (i.e. you are tethered to your Blackberry).
Finally, always remember that outdoor recreation has historically been for the privileged class. If you work minimum wage in an outdoor job your whole life, you may not want to spend hundreds of dollars on gas to make a trip to Yosemite when you have, say, a doctor's bill to pay off. Farmers are outside all the time, but most of the ones I know are pretty much tied to the land, working 12-14 hour days 6-7 days a week during the summer (when most of us are taking our August vacation).