Good question. Although many of the responses you received on this topic highlight some of the better aspects of engineering, they fail to present the whole picture (but that's what you get when you ask that question at an engineering based website!)
Just to give you a little background on me: I'm currently a mechanical engineer in the aerospace industry (after spending some time in the semiconductor industry and injection molding industry). I received my BS and MS in mechanical engineering from an accredited university, graduating with high honors from the MS program, and landed a decent paying job back in 1996. I participated in co-op programs as an undergrad, was involved with many engineering related activities in my hobbies, and was always good in math and science. It seemed that engineering was in my blood until I started working....
- Engineering school was fun, engineering hobbies are fun; the bottom line in industry is all $$$, and you end up having to do things not because you enjoy them, but because they're good for the bottom line (they'll disguise this fact by referring to your project as a "creative challenge"). A sure way to kill your passion for engineering.
- Engineers are introverts, many of who lack the most basic of social skills, couple that with sitting behind a desk for 20+ years and you end up with co-workers who aren't exactly the life of the party. You'll be spending at least 8 hours a day with these people, so make sure you can deal with it.
- The pay starts out nice, but flattens out rather quickly. Sort of like a step function. As someone else mentioned, you won't get rich from engineering (a reality that sets in when your faced with huge college loans to pay off some day).
- Cubicle world. Read a few Dilbert cartoons - it's scary how accurate Dilbert is.
- Diversity (lack of, that is). A male dominated profession that doesn't seem to be changing.
I could keep going, but that should give you an idea of the other side of things. Of course much of it depends upon where you get a job and what your specific role is, but I've had several friends leave the field of engineering, and many who are trying to find alternative means to make a living because of those items listed above. If you can avoid these pitfalls, then engineering can be rewarding - I have managed find some fulfillment in engineering consulting, where I can pick and choose what I work on and don't get bogged down by the bottom line. There are many areas of engineering, and with every career choice some jobs within that career are better than others. The truth is that you can only decide for yourself once you get there - there are no guarantees that it'll be worth it. Probably the best reason for getting an engineering education is that it can be used as a stepping stone to go almost anywhere (I'm heading towards commercial aviation). So if you can hack the hard work then it can be a very useful asset for you - just don't think of it as an ending point but more as a tool to get you where you want to go.