I'm a big fan of the FiberPlus bars by Kellogg's. One bar has 9g of fiber and they taste awesome: http://www2.kelloggs.com/ProductDetail.aspx?id=16011
Also, the FiberOne bars are pretty good, but they are a little more dry and bland compared to the FiberPlus bars.
I just buy what's on sale at CostCo. and go with them. Out of those two brands, I haven't found a bad flavor.
Just make sure you're having a protein shake with them!