I own every type brand size of luggage made and all of it has gone on one cruise or another in the past year. There is a graveyard of luggage in the garage that is no longer allowed to cruise because it's: Too deep to fit under the bed in cabin, too cumbersome to wheel when weighted down, Too big and heavy for airlines and too small inside.
The luggage many of you got at Christmas is perfect by the way
Two suggestions: Drop bags at pier early if possible. If flying, remember that most airlines will not allow you to check bags earlier than 4 hours before flight, so you will be wheeling it around at the airport if early.
The plastic tags that attach with wires to hold cruise ship tags are well worth the money!