Yeah. From what I've come to understand, there's definitely an ideal gear ratio for a particular rider and his particular circumstances.

I have the luxury of having a relatively flat area, so changes in gear inches are not as drastic terms of difficulty for me. I run 46x15 and will soon be running a 48t up front. Eventually, I want to see that cog go down to 13t (too lazy to check if they make those). When I top out (assuming I make it) to a really tall gear, I can then play around to find my "optimum mega fixed gear ratio".