There are several kinds of mappings. Some of the more complex ones have been broken down and been explained in detail. Again, some explained examples can be found in my vimrc. Generally I prefer abbreviation to mappings in insert and command mode as you can see what you type, while mappings will wait either for you to end the mapping or for a timeout. The list will probably be expanded as I setup more language specific mappings and abbreviations.
Any comments are very welcome.