Sometimes I have a task which can't be started for weeks or months. I don't want it cluttering up by to-do list until then because it's a distraction from genuinely do-able things, but if I put them on my calendar then they'll vanish into invisibility the moment they're overdue. In these cases, I use a tag called "ontheday". My main to-do list is a Smart List with the following filter:

dueWithin:"2 days of today" OR dueBefore:today OR NOT tag:ontheday

This list now contains all my regular tasks, as well as any 'ontheday' tags which are overdue or due soon. I can happily forget the others until they appear on the list.

(Occasionally the 2-day limit isn't really appropriate, but if I set the due date to when I want it to appear I can always sort it out when it arrives and it's much easier than having graded tags and a longer search filter.)