And if you use a triple in front, you have 243 gears!

I have a DualDrive on my Bike Friday and I feel like I have the best of both worlds - the wide range of a derailleur plus the ability to shift (the IGH) while stopped. Not having a front derailleur simplifies things somewhat, too.

Many people are happy with 7 and 8 speed IGHs. However, one of my friends experienced premature failure on both a Shimano nexus 7 and later 8 speed hub. (On a trek navigator). The failure may have been related to the fact that he road in dusty conditions, or that his bike was pretty heavily loaded, or to some other unusual reason...but it has made me a little leery of conventional 7-8-9 speed hubs. (Although not the rohloff; I think you could use that to drive a car).