I think that the good things you want to do are great to overcome (or in spite of) your depression...

IF

and ONLY IF

you have the courage to admit that those good and hopeful things you want to say to all those other people who need help apply to yourself as well.

You can't go to some poor kids in Africa who have lost their parents to AIDS or guerrilla warfare and famine, and who don't know where their next meal is coming from, and say, "Hey guys there is a better life ahead of you. Come to America where you won't have to deal with all these problems, even though life over there doesn't have any meaning."

NO, you wouldn't want to say that to them, right? You want to play "Help the Children" for them, not some Nirvana song.

I think Depression can give an insight but it is like something that helps you to say, "The heck with this." It is not something that you can learn to appreciate or cohabit with, because it will just want to keep taking more and more from you. It gives insight in that you have a special knowledge or sensitivity to things that many others miss, and you can transform that into a positive action or helping others. That's the only way it will be insightful.