Apologies if this has been covered before but I've been trawling through hundreds of posts without success.
As the European and Asian airlines are so stringent with weight allowances, I was wondering which were the lightest cases on the market (either for hold or carry on) and if anyone has any personal recommendations.
My back isn't so strong, so wheels are very much preferred.

(I was looking at shops in New and Vegas a few months ago and I couldn't believe how heavy most of the cases were - guess most Americans don't have to worry about our miserable 20kgs allowance)