So far I've been trying to use Vim in as vanilla a configuration as possible, so as to save myself hassle when moving between machines. However, there are a few things I'd really like to bind keys, such as to shorten "_diwP which I use often to delete the word under the cursor and replace it with one from the clipboard. Are there any particular keys that are conventionally reserved for user-defined mappings? The point of this question is mostly that I would like to avoid hassle later on when I decide to install some plugin or take my configuration files to vim on another OS and find that my key mappings clash with something else.