My advice is don't go cheap and don't go overly expensive. Be mindful of the empty weight of the bag. If the bag weighs 18lbs. then you've used up 36% of your allowed weight.
The 360 degree rolling luggage is nice and I may purchase a set of that when my luggage finally gives up the ghost.
I have a set of "Jeep", yes Jeep, rolling luggage that we picked up at TJ Maxx of all places. The set consists of: 2, 26" cases, 1, 24" and a rolling carry-on. The 26" suitcases weigh just over 10 pounds. They have been on at least ten cruises and close to that many other trips in the last few years and they are still going strong.
I also have a, higher end, Samsonite rolling suit bag. I had the same "non-rolling" bag for over 20 years and it had close to a 1/3 million miles on it. About three years ago we bought the same bag but with rollers. I would guess it has three or four more trips left in it. They just don't make them like they used to.
One last thing. If you think your luggage is ready to give out. Don't take it. It is one big P.I.T.A. to deal with broken or destroyed luggage.