I have reams of arcane bits of information to commit to memory already. .Net in two languages plus VB6 for legacy code. SQL in more dialects than I care to list, each with their own quirks and limitations. HTML and JavaScript. XML and various associated technologies like XPath. That's just professionally; once I go home I can add in photography and music straight off with others at different levels.
There's only so many things one can usefully commit to memory (edit - yes, I meant am prepared to dedicate the time to committing to memory); odd bits are just easier to look up. So why, exactly, should I voluntarily use a text editor whose interface was already far behind the state of the art when I started school?
:q!. I've had others try to persuade me of the joys and power of vi; I'm not even slightly convinced and that is the one command I'm committing to memory.