I generally like luggages made by American Tourister or Antler. They come with 10 years warranty, and generally on 30-50% off sales at Metro and Parkson.
A dodgy luggage can be a surefire way to ruin a holiday experience if they break on the way to your destination - even if you are covered by travel insurance.

For short trips, I generally like the 50L hybrids (roller with shoulder straps). This size means you don't need to check it in. These can generally be found from any reputable camping store.