In reply to phmcguin: I'd have a think about how you're going to use it.
I have an extra large and two large ones (as it were). The XL was bought first and was enormously handy for trips to the USA, back when the baggage allowance was 75 kg; just chuck everything in and get yourself down to the airport, job's a good 'un. But now baggage restrictions have become a little tighter and many carriers will force you to pay extra not just for baggage that weighs more than it should, but for large-size bags too. The XL may cost you extra to ship by plane.
The baggage size restrictions seem to come in most commonly at a total size (H x W x D) of 62" and the L duffel just scrapes under this. So for my next trip instead of one XL and a hefty surcharge there'll be two L's and nothing to pay. If you're going to be doing a lot of travelling by plane it'd be worth finding out more about the restrictions the carriers you're likely to use put on baggage size before you spend your money.
When not travelling the XL contains all my climbing gear, rucksacks and all, in one handy place and the two L's are full of bedding.
T.