Ben Witherington asks this question on his blog. The answer he gives is not always easy to swallow but healthy nonetheless. While Ben responds directly to the message of Joel Osteen, the response becomes more poignant to us (to me!) when we realize that we need not be a part of the "faith and wealth" movement to succumb to the cultural pressure to acquire more and more stuff. Ben reminds us (me!) that being Christ-like has implications for how we treat money.
If you are praying prayers Jesus would not endorse, selfish and self-centered prayers, prayers about purely material success then you had best not sign Jesus' name to them, nor should you expect him to answer yes to them.