I have not been interested in this question for a long time, but a fresh Netcraft Web Server Survey has just turned up. According to the study, the share of Apache over the past year and a half has greatly decreased. The same graph demonstrates the growing popularity of the Microsoft Platform, which apparently speaks of seriously gaining .NET-based solutions.
All Domains August 1995 - January 2007
UPD: Somehow strange Habr copies the pictures, the original can be viewed here .