I just threw a couple small PHP classes up on GitHub that I use in almost every WordPress plugin I write. The first is IDAdminNotices, which is a clean and easy way for plugins and themes to send messages/errors to the user within the Administration Panels. The second is IDDescribeVar, which will outputs the type, length and contents of a variable in a readable format, and send it to wp_die(), die(), return, set_transient(), or an IDAdminNotice.