In My Jesus Year: A Rabbi's Son Wanders the Bible Belt in Search of His Own Faith, Benyamin Cohen says the following about the prosperity Gospel:
"Although Judaism has similar notions about prosperity--our prayers often ask for sustenance--it is, by far, not the highlight of our service. We do not worship the almighty dollar. If we're asking for anything, it's usually for stuff like health or good tidings. But the focus of most of our prayers is praising God and actually has nothing to do with our wants and needs" (67).
I think there needs to be balance. When I watch Joel Osteen, for instance, I'm usually encouraged by his messages, since he gives good advice on how I should live my life. But he mostly focuses on giving us tips, which he often supports with Scripture. I don't see much about praising God. I think it's good to offer people hope that God will make a breakthrough in their lives. But focusing entirely on how God can bless me and make me prosperous can get pretty empty after a while, in my humble opinion.