A year or so ago, mostly due to laziness & privacy paranoia & the MtGox leak, I got into the habit of having my password manager generate (and autofill) not just random long passwords for each website, but also random long usernames.
I'll undoubtedly regret this methodology if I ever have to manually type or memorize any logins. But hasn't been a problem so far, aside from the Bitcoin conference: whenever I wanted to tell anyone my username on this forum, I just couldn't remember it, and gave up on the time-consuming process of looking it up on the mobile phone. Anyone who met me there could (I hope) certify I'm not scary in real life