I travel with this one:
http://www.amazon.co.uk/Rimowa-Salsa-Deluxe-Cabin-Trolley/dp/B001Q6ZIJK/ref=sr_1_1?ie=UTF8&qid=1308158008&sr=8-1
(I have the regular version, and it was cheaper (280 euro) where I bought it from, but this gives you an idea).

When I moved to the US, my parents gave me one of these Rimowa suitcases, and I’ve been totally hooked ever since. After my regular carry-on broke down, I decided to get this one. They’re incredibly strong and incredibly light at the same time.