I'm a huge fan too! I like peanut butter the best, I usually have one for breakfast, or a snack in the afternoon. I'm going to try GNU bars too - I saw the promo on this site, and they have 48% of the fiber you need in a day. Maybe I'll switch off between the 2.
I just bought the peanut ones. I think they're great. They are filling and they take a long time to chew which I think is good. Yes, they sell them in any supermarket. I am keeping the box in my car, this way if I'm out and about and get hungry I have something that can hold me over.
I eat one every single day...they are a staple to my diet. Love Love Love the chocolate ones...they actually stave off chocolate cravings for me...yummy! Well worth it...I found the best buy is at either Sam's Club or BJ's Wholesale club...they have a much better price on them!
Before they were invented, I made my own "granola bars" out of the original Fiber One Cereal...more as a breakfast substitute than a snack. When I get home from work, I'll post the recipe if anyone is interested.