GtoRA2, you should read "Man's Search for Meaning" by Viktor Frankl.
Personally, I think the meaning of life is to help others. We're here for the people we come in contact with (especially those we cherish), and they are here for us. A man may not be able to measurably affect the whole world, but he can affect the world of other individuals that he touches in some meaningful way. Cue the obvious Catholic priest joke.
How many people here wish they lived during WWII so they had a worthy endeavor, a noble cause to live and even risk death for?