I think creatine is awesome (I'll get to the negatives soon) for:
1.) Temporarily Building muscle (unless your body type is already bulky, you're not going to get huge).
2.) Increasing strength
3.) Increasing muscle endurance
4.) Increasing energy
5.) Psychological boost may get you into the gym. If you don't lift, it won't do anything.
NOW, for the negatives:
1.) If abused, like everything else, it can cause negative affects which are not all understood at this time.
2.) If you stop, you lose muscle mass quickly (due to retained water when on the substance)
3.) I got a bit of a gut once I stopped. Horrible.
4.) Who the Hell knows what harm this can cause if used long-term
While it sounds like I may be endorsing the substance, I will NEVER use again because of the side effects. It's really a short-term fix and your body will return to its natural form once you stop. Consequently, like others have said, AVOID taking. A better option would be to get a committed work out partner and work hard in the gym. Remember, just about everything meaningful in life requires hard work and persistence. Creatine is a quick, temporary fix that could be dangerous.