As other people have mentioned it really depends on what you want to do. My wife's new Asus EEE PC has the N450 Atom and it is fast enough to use Eclipse and write Java applications (including quick compiles). But try and run the Android Emulator and it doesn't have enough horsepower (lack of memory is my guess). Took over 10 minutes to boot the emulator.

Which is why I have the Asus K50 dual core pentium. And it still weighs in under 4 pounds even though it has a 15.6 widescreen. I travel every week so having to drag this laptop and my work laptop means that the less mine weighs the better it is for me.

I have not tried to watch a DVD movie yet. But I use Slingbox and it works just fine to my DVR at home.