When I booked my first Rick Steve's tour, one of their rules was to pack light since you were going to be carrying and handling your own luggage at all times. By then I had already gotten into to habit of putting things in large ZipLock bags in order to get organized. I knew large ZipLock bags although handy, do not last long, so I decided to try travel bags. I bought a couple from Lewis and Clark, and some from Eagle Creek. There are also a more economical version in your " As seen on TV" Space Bags. They all do the trick but my favorite are the Eagle Creek brand. Hands down they last longer than any other brand.
From travel bags I moved to the Eagle Creek packing system, they really help you organize your luggage and keep everything accessible. Nowadays, there's nothing in my bag nowadays that is not perfectly contained in some sort of packing cube, envelope or bag. Give Eagle Creek a try , you will not regret it.
Last year I decided to upgrade my 19" rolling suitcase which I bought in Target for $60 and that it's still holding on strong after rolling around five countries in Europe, countless trips to Las Vegas, Puerto Rico and I can't remember how many other cities in the U.S.; really it's only fault is that it is black. Around Xmas season taking advantage of available sales I bought a 19" red Delsey Helium 3.0 spinner for my 3 weeks in Italy. I have only one thing to say: "Thank GOD for Lifetime Warranty", unfortunately although super light and spacious enough for a 3 week trip with room to spare, the wheels did not handle well the cobblestones in Italy and its hilly towns. One a good note upon my return to Florida I was able to find an authorized Delsey center which replaced the wheels at no charge. Other than a good packing system and a good suitcase, it doesn't matter if you fold, roll, stack your clothes, the secret is don't be afraid to mingle with the locals and get out and DO LAUNDRY!!
Also check with your airline as nowadays even though a 19" suitcase is advertised as a carry on, fully packed it may exceed the overhead space capacity.