I joined Cub Scouts in 3rd grade, and made it through Eagle, and Vigil OA. I'm still involved whenever I can get the time. I worked 5 summers at the same camp as Snorkel_Bob. The BSA taught me most of the stuff that I love to do now, including shooting, hiking, backpacking, rock climbing, horseback riding, wilderness survival, sailing, and all that other cool stuff. I think it's one of the best programs out there. The BSA is what gave me most of my love for the outdoors. I also concur with everyone else's comments that you get out of it what you put into it, and you should spend some time checking out the various troops in your area, and pick the one that has the most opportunities.
I happen to think that, in general, the program is getting a lot "softer" recently, and becoming more PC (which I hate), but there are still plenty of opportunities to have fun.