i just recently moved so i will share what i did...
I put my fish in my small 5 gallon tank and dropped the sponge from my filter in along with some tank water while i cleaned out my 55 gallon. I then completely emptied the big tank and took it to the new house. Of course, i was just moving down the street, so i went and set up my 55 gallon at the new house, i saved the filter media (sponge and biomax) becuase that's where the good bacteria is. I went ahead and got it up and running, i replaced the gravel with new natural looking gravel, so i took some of the old gravel and put it in some panty hose and dropped it in the tank.I also added dechlor/water conditioner to the tank adn went ahead and planted my plants.
I went back to my old house. I then put my fish into a one gallon tea piture, just for the 15 minute ride across town. I also thought about putting them in bags like the fish store does, which might have been a better idea!
To get them used to the water, i actually floated the tea piture in the tank with the handle hanging over the edge. I added about 1/3 cup of water from the aqurium to the piture every 5 minutes for about an hour and then netted them into their new home. I still have all of those fish from the move, alive and well
But i kept the old gravel in the tank for a week before i took it out, and i still have the same sponge and biomax in the filter, but i added new carbon of course. I have been testing the water every other day for the past two weeks, and i guess everything went ok, becuase my ammonia and nitrites stayed at zero.
Good luck with your move!