One thing that many people overlook when packing for a move is a tape-gun. While you can do without one, if you have a lot of boxes to seal, it makes the job a whole lot easier. They're relatively inexpensive, and it's a snap to change out tape rolls when you run out.
When you're moving, it's a good idea to get the sturdiest boxes you can. This helps eliminate the problem of crunching, in which your boxes are crushed by the other boxes stacked on top of them. Sturdier boxes might not be the cheapest, but they'll be worth the expense in the long run.