For a while when I signed up at a website for some trial thing, I would use @muddylaces

If I get a bunch of spam at that address, I can then create a mail rule to just delete all mail/bounce it/black hole it/whatever.

Also (and this is a lame reason) I always advertised my email as gfox, but some people used greg. The catch-all did it's job and I still go the mail.