What laptop are you using for travel?

I bought at costco and use a WD 160 GB external usb drive. thin light works great

Sony Vaio TX series, tiny, long battery life and built-in DVD burner for under 4lbs. Load up on ram. Expensive but worth it.

If you are desperate to cut weight and will only use the laptop plugged in you could consider leaving the battery pack at home. Probably saves enough weight to bring along that external harddrive. Just remember that by doing this you loose your build-in UPS, so if power-supply at your destination is unreliable you better save your work regularly.

Bart

I had a tiny Dell that weighed in at just under 4lbs. The screen crapped out so I bought a larger Lenovo (IBM).

It's not the smallest model, but it's fairly light. The difference is I can type like a normal person. The Dell keyboard was too crammed or my fingers too fat.

I have a portable hard drive to backup files. It is powered by the PC so no power cord.