Ah, we are experts in this area! In a span of 6 months, we moved for a 2-month assignment overseas, then moved back to our "old" apartment in DC for one month, then moved overseas again, where we were in a hotel for one month, then in a new house. Same story with the schools, obviously. My daughter was 2.5 at the start (so 3 for the last move). I always thought her to be a very spirited girl and worried about her being overwhelmed by so many changes (which also included an almost 2-month separation from Daddy during the latest move), but she has been amazingly resilient and has taken it all in stride and quickly made herself at home. Given that we were moving overseas, there was no time/opportunity for easing her into the situation. With neither move did she even have very many of her toys, just what would fit in a suitcase (books, puzzles, etc.) until our shipment arrived. I felt bad but she coped up much better than expected with so much change (though it put us behind on thepotty training, which has been a more recent victory).
So, based on these posts, you have options - go all out and make it an exciting transition (the 22:19 poster sounds like they had great fun!) or make it a total non-event. I think you really need to "read" your own kids in terms of how well they handle change. In either case, I would pack up their stuff last, preferably when they are not at home, to avoid either tears/tantrum or the packing/repacking/repacking/repacking fiasco (my daughter likes nothing better than to empty out a box and she does it faster than I pack it up!)