My 2-cents below. I've worked as a concept artist for a year and an environment 2D/3D artist for 2 years.
-You get to make art for a living. Not many people do. You won't get to make exactly what you want all the time - in fact, you almost never get to do exactly what you want, but you are getting steady and reasonably nice paychecks doing art. (It's awesome.)
-You will be working with many nerds who share your interest. Coming from a completely different career where I have nothing to say to my hip, trendy coworkers, I can tell you that's a HUGE bonus.
-It's a relatively small industry and you'll quickly get to know a lot of people from all over the place. As long as you don't burn your bridges, this is great when you are looking to move around in the industry.
-you will more likely than not be required to work spurts of overtime, aka "crunch time". Some companies pay you for it, others don't. You will not have as much time for your family as if you were in a regular 9-5 job. Plus, if you are a dutiful artist, you'll want to get some art done on top of this, which leaves you not very much time at all. Time management is a crucial skill.
-you will never look at games the same way again after working for a short while. This may not be bad depending on the person, but personally for me a lot of the make-believe magic is gone - I look at games and see exactly where the boundries are, where I can or cannot go, can or cannot do. I still play games and have fun but some of the illusions are not there anymore.
-competition is fierce. You need to give it all you've got, be completely open to critiques from online or in person (and lick your wounds in a corner instead of biting the hands that feed you.) You need to actively seek out networking without being really annoying or creepy. Showing people your work and asking for feedback will be a good way. Filtering through and acting upon these feedback will be equally important.
If you are motivated enough, you do not need to go to expensive schools. Get your portfolio together, use all the online resources out there, and visit game developer conventions and local sketch groups. It's not an easy path and you'll have to do all of your networking yourself, but you won't have to worry about expensive student loans later. If you can't stay structured without school (like many other artists) however, go to school, work your butt off, and focus intensely on your portfolio. It's worth it - once you find a job you love, you won't have to join the masses who spend their days counting towards retirement.