Custom Exceptions, Inherit from what type?

I have heard ApplicationException. I have heard Exception.

From a MS source:

"......originally ApplicationException was intended to be derived from, however we've changed our tune on that one given how the hierarchy ended up developing. The new guidance is to derive directly from Exception in all cases where you would have derived from ApplicationException.  The guidelines on MSDN still have the old text. We will be updating  them, but probably not until after Whidbey goes out the door. As it  happens, there's some discussion of the issue here:

http://blogs.msdn.com/brada/archive/2004/03/25/96251.aspx.

"