If you are being moved by contractors (Mayflower, Allied, etc) then make it easy on yourself, have them do the unpacking. It's part of their contract, so it's not an additional charge - and when they're done they take all the boxes with them. Of all the families I've seen move (there have been lots!) I don't think I have seen anyone besides us take advantage of this.
They'll say "oh, the movers just dump everything, they won't put it away."
True. But it's a lot harder for you to ignore all those piles of stuff than boxes. This way you are forced to take action.
They also say "I don't want the movers handling all my stuff."
Um. too late. And there is a way to work around that, but that would be an entirely different post.
And if you aren't so lucky as to have strangers rifle through your belongings and leave them in piles on your (hopefully now clean) floors, then it still has to get done. You could use the same method, just unpack it all at once. Our most recent move was a DITY (military speak for moving yourself) since we just moved locally. We had movers handle all the furniture but the "stuff" - that was all us. Mostly me. I used Rubbermaid containers for most of it. And a few laundry baskets. But I only had so many. So in order to get everything moved, I had to unpack right away - so I could run back to the old house and get more stuff.
Unpacking is a lot of work. A lot. But, you can't get things put away while they're still in boxes. And like I said, it's a lot easier to shove stacks of boxes to the side and say "oh, I'll do that when I have time" than to ignore piles of crap everywhere.
Maybe you're still not sure where everything will go? There is one way to figure it out.
And I guarantee, when you first saw your new home all empty and full of promise you didn't squeal "oh yes! My 16 boxes of craft supplies will fit here perfectly, and we can dig through the dish pack every night before dinner in this EXACT spot!!"
One last note, if you have little people. There is a benefit to unpacking - besides not leaving their childhood memories full of cardboard and unfound belongings - a yard full of empty boxes is a total. kid. magnet.
So, if you have boxes stacked somewhere, still unopened - pull 'em out. You may discover a lost treasure (OMG! So that's where it's been!) or just a bunch of crap you can live with out after all (why do I have this?).