I just returned yesterday from one month at Siem Rieap, one month in Nepal mostly trekking in the mountains, and 3 weeks in Thailand. I took with me a very compact Dell laptop with 80GB HD & DVD drive, a LaCie pocket 100GB external drive and about 20 blank DVD discs.
Before I left Cambodia, I'd filled the LaCie external drive, used all the blank DVDs and had to buy another 25 DVD spindle of blanks in Siem Reap.
As a rough estimate, I've shot about 200GB of images on my 5D and 20D, all recorded twice on a combination of either the LaCie external drive, the laptop HD and/or DVD disk.
The temples around Angkor Wat are the most amazing photographic opportunity on the planet, but there's one major drawback... those damned tourists!
They get in the way all the time. It seems everyone wants to be photographed standing next to, or in front of, anything amazing and wonderful. Sometimes a tourist guide leading a group of 20 or so Koreans carries a bag containing all members' P&S cameras. The whole group will pose in front of some amazing root structure growing over a ruined temple, and the guide will slowly take a photo with each member's camera, sometimes having difficulty operating the camera, which causes further delay. In the meantime, yours truly is waiting patiently in the wings for the crowd to disperse, wondering if any purpose will be served by returning half an hour later, by which time another group might well have taken the place of the first group.
BTW, I lost 10kgs trekking in Nepal. Better than any diet .