I take a small hard Samsonite carry on size that I check in and one carry on that has my laptop and camera and other personal things in it. I can pack a week's worth of clothing in the one I check in and use the laundry or send out clothes to be laundered and pressed if I have more than one formal night or run out of clean clothing.
I used to pack like a mule for a cruise, but no more. I NEVER wore all those clothes I took and now I only take 4 pairs of shoes at the most...walking shoes, loafers, dress shoes and sandals.
What's nice about Carnival is that they have guest laundry services and you can do some laundry if you run out if you're on a longer cruise.
hubby & i shared a large suitcase and carried some bag on with 1 change of clothes if needed for the 1st night. that little bag also had meds, etc. in it. the kids shared a larger suitcase and each had a carry-on type bag with a clothing change, books and other entertainment/personal items. that was for a 5-night. both suitcases have outside zippered pocket and let me tell you - they were full to the max. we just decided it was easier to have 2 heavy suitcases than try to wrestle with a bunch of smaller ones. not sure what we will do this year, as it is a 7-nighter.
i only took sandals, tennies and water shoes, as did hubby & son. daughters took tennies, water shoes, sandals, flip-flops (who knows how many). they also took hot rollers, curling irons, makeup, jewelry - i really don't know how they got it all packed.
For a 7 day cruise, going to port 2 days early, I use a 26" expandable suitcase and I take a very small (12 x 9 x 7) carryon. I have learned to mix and match all my clothes so I don't need too many. 3 pair of shoes (1 dress, 1 sandal, 1 walking shoe).
Voyager of the Seas 5/03
Celebrity Solstice 2/09
Oasis of the Seas 10/16/10