Littlefoxling wrote a recent post on the issue of meaning and I've been giving it some thought of late. (Not that I have the time for this and it is eating away at my studying, but that help explains why I'm writing this post at 2 am.)
Essentially you have two general approaches to finding meaning in life. The first is for meaning to be found in something bigger than oneself. This includes the classic religious approach where meaning is found in being a part of God's master plan and each of us have a mission in life for which we were specifically created. We also see this in the more secular nationalism or humanism where the good for society or humanity in toto is the good to which one's life is given meaning. It is in service to the public good to which our life is worthwhile. These two aspects are not incompatible and indeed we often see political leaders (Republicans typically) who invoke their belief that their public service is their place in God's plan or that they sought to serve the public because they believed they could further God's plan.
The second approach for meaning seekers is introverted and is the classic view of existential philosophy. They say that the rest of the world is impossible to value objectively and therefore obtaining a sense of meaning from a valueless externality is hopeless - vanity, as it were. So the Existentialists seek to understand themselves as subjective beings and best authenticate their lives with integrity. I am who I am and being true to myself is the meaning of my existence.
It's interesting how both of these paths are essentially non-materialistic, if well applied. Seeking God's will or the common good obviously transcends the immediate desires for creature comforts, but even existential authentication retreats from "selling out" or becoming an empty cog in the machine. If you are familiar with the movie Fight Club or Randian protagonists, you may recognize this theme. But I'm not trying to intimate that one path leads to global prosperity and the other to violent anarchy, but that both depends on the underlying ideas behind these theories. If God is good then finding meaning through God will lead to good. If you find your authentic existence is to be a good person then it too will lead to good. These may both be reversed if you're contemplating joining Al Qaeda.
Anyway, it could be that both of these approaches have their places and that some synthesis can be made of them. To put the meaning of one's life completely on the other empties one's personal experience, but to lean wholly on the subjective leaves one contextless and lost. Classically: "If I am only for myself, then what am I?"
So I would encourage self-investigation and being true to oneself because ultimately we each walk down life alone and it is only through that path that one can find out who they are and what matters to them. This is the soul of man. But I also say that some faith in the meaningfulness of our surroundings and the human condition is not out of place. Although some are skeptical, I do not believe that our existence is an accident. And from that realization comes the conclusion that we hold some honored place in the grand scheme of things. Whether there's a mindful Schemer or a non-conscious Orderer is not so important as much as our place in the order of things. From this follows the valuation of human beings and human interests generally.