In my cupboard are Kashi Go Lean, Fiber One Original, and Flax Plus Pumpkin Raisin Crunch. The last one I got at Costo while visiting my parents (I don't have a membership) so it was a good deal in a big box, and I like the taste. However, the smaller boxes at normal grocery stores are just about the same as the big one, so I won't be getting a refill - I'm getting the Kashi Go Lean cereal instead.
I haven't tasted it yet, but it has more bang for the buck (protein/fiber) than any of the other cereals I found. Also, a word of warning, around here it costs ~$4.50 at Safeway, but only ~$2.50 at Target (if you have those). I bought mine at Safeway before going to Target.
Fiber One I add to everything, including my other cereal, for a big fiber boost.
G'luck choosing!