Google has a firm grasp at the top in terms of popularity & market share. Will they be able to hold their position long term? No serious challenges seem to be looming for the search giant. I will go out on a limb here and predict they will remain the leader for at least a few years. predicting beyond that would be foolish. The internet oas a whole is not very old so it is a lot like the proverbial "dog years" say like 3 months is one internet year... or something like that.
Most webmasters use google and webmaster do a lot of searching. I wonder how this affects their stats? i say it skews them upward and generates a high number of what i would call "junk clicks". IMHO