I have an Akona Evolution Roller Bag that I bought for my upcoming trip. It does me no good to have a really big bag because I'm restricted to 20 kilos (44 lbs) for checked bags (only one allowed) and 10 kilos (22 lbs) for carryon. I'm also allowed one personal bag. (hoping they'll let me get away with my backpack). They packed 47 lbs into this bag when they did the scuba lab tests. I won't be taking as much gear as they used for the test. I'll fill in space with t-shirts and shorts which weigh less, so I should make it. I have a Pelican Case for my camera gear that meets the 10 kilo requirement.
It seems that only flights headed to and from the US have the more generous baggage allowances :-(
Here's a link for the bag I have:
http://www.akona.com/product.php?product_id=112 Here's another link for a review on full-size bags:
http://www.scubadiving.com/gear/bags/hot_wheels