Of all the protein bars out there, the Builder's Bar by Clif are my favorite.  The flavors I have tried are peanut butter, cookies and cream, and chcocolate mint.  They all taste great and the peanut butter is my favorite.  
I use these as a snack in the afternoon when my energy is low and I know that I have some sort of rehearsal or activity after work.  I also use these on long bike rides (50+ miles) to make sure I'm taking in protein and not just carbs.
I really like that the ingredients are natural and that the ingredient list isn't comprised of chemicals with unpronounceable names.
I honestly have no complaints about the product and have been very pleased with Clif Builder's Bars.

One of the better meal replacement bars I've tasted - can't really tell difference between cookies and cream and chocolate, but they're both great.  Easy way to grab a decent snack on the run.

Great tasting, healthy snack.

Better tasting and more nutricious than any other bar I've tried! Packed with protien, these bars are made for people like me who burn through calories and can't stop for a meal. Love them!