Wait, are we walking about finishing high school, or college? There's a huge difference. If we're talking about High School, then I agree with Jess.
I don't care what you're skills are, if you can't finish high school, changes are you can't use your skills properly. I can't think of anyone successful I know who didn't finish high school, and that's because I don't KNOW anyone who didn't finish high school. At this point, at least in the United States, it takes much more effort not to graduate high school than to actually graduate.
Now, if we're talking about a college education, then I agree for the most part with diuqscirtic. A college education is great, most people should get one. But it is by no stretch of the imagination a requirement to be successful. One of the most successful and wealthiest people I know is also one of the few I know who only has a high school diploma. I also know people who graduated college, and from good colleges, who aren't successful... But, these people are the exceptions. In reality, graduating from college can't hurt.
But for people who go through college like "must have 4.0 GPA", I just find that sad. Graduating is graduating. I always look at it like this: you go for a job interview, and you're competing against someone who graduated college with a 4.0 GPA, but you have a much better skillset. Of course they are going to pick you. Any company that knows what they are doing knows how to spot talent and not just look at a meaningless number.