I'm looking for a new x86 portable so I'm looking for recommendations for the best laptop/netbook/ultrabook which has the longest battery life. I'm currently looking at the Vaio Z or the X220 but any suggestions for x86 systems with long battery life are welcome.

Atom without a doubt. But it's really slow.
If you can, grab an AMD Fusion Brazos E450 chipset.
A great example is Asus EEE 1215B. 7 hours of battery (tested it by myself). Will even play videogames with that rig. Is really impressive.

I've been looking for a 1215B but can't find a retailer that I know selling it. They all seem to sell the 1215N which I guess might be just as good. I've also been looking at the Vaio S before the half price processor/memory upgrade expires but the configuration process is confusing/vague.

Has anybody ordered from the Vaio site? Is the SSD worth it?

The reason I ask is because if I order the 500GB standard drive it's £175 cheaper which is about the price of a 128GB drive anyway. Is there something particularly special about the drive Sony is offering? If not I could just get the 500GB drive and install an SSD myself.

Macbook Air 11".

best life. I charge mine once a week with daily use (not heavy).