Tim,

I pretty much follow the internal coding guidelines from Brad Abrams blog:
http://blogs.msdn.com/brada/articles/361363.aspx

The highlights are:
Do not use Hungarian notation
Do not use a prefix for member variables (_, m_, s_, etc.). If you want to distinguish between local and member variables you should use “this.” in C# and “Me.” in VB.NET.
Do use camelCasing for member variables
Do use camelCasing for parameters
Do use camelCasing for local variables
Do use PascalCasing for function, property, event, and class names
Do prefix interfaces names with “I”
Do not prefix enums, classes, or delegates with any letter
The reasons to extend the public rules (no Hungarian, no prefix for member variables, etc.) is to produce a consistent source code appearance. In addition a goal is to have clean readable source. Code legibility should be a primary goal.