I tried to declare a simple instance of string named "n". Since ReSharper 4 this becomes a tedious undertaking :) As soon as I type "n", ReSharper inserts the template for "nguid".
in order to reproduce, create a class in C# and declare
string n = "...";
exp: no change of code
act: n is being replaced with nguid as soon as you type the space after "n".