I've just purchased an ACER Aspire M1640. After unboxing it, I installed debian etch, upgraded to lenny, and am now going through the process of testing its power capabilities. Right out of the box, the computer uses between 40 and 70 watts. After my initial tinkering, I've been able to reduce that to about 35 watts. Pretty good, huh? I'm also happy to report that S3 sleep mode is working, which reduces the power down to about 6 watts.
I still have a bunch of testing to do and more documentation to write up, but so far so good. I'm glad this machine is efficient and flexible.