I ride a 2010 Trek District 2. It is a SS/FG as it has flip-flop hub (I have it set to only SS). Used to ride a geared bike but found myself never chnaging gear and always wanted to try SS. That was enough for me to get one and never look back.

As other says, it all depend on the area you are. If there is a lot of hills, some folks might say that you are just crazy. Not me as I see them as a challenge and a very good way to keep improving your strenght. Hills, downhill, winds.. all that is part of what you will hate at first but get use too it after a while. Just have it geared the way you like it.