I have an application that uses one web service asmx file per screen (like 50 screens), I didn't think this was a problem until we did tests.
I tried with IIS7 on windows 2008, it hanged. Since its new to me I changed it to IIS6 on windows 2003, the same thing happened
IIS 6 creates tons of w3mp.exe processes, each 55 MB, and reaches a point where the application is usless.
It has been used only by 10 people at the same time...