[klaasvakie]

I'm getting ~8 hours with wifi with Ubuntu 12.04 on an Asus Zenbook UX31E. Everything works out the box with no tweaking, see here: https://help.ubuntu.com/community/AsusZenbook

If I had to buy now though, i'd get the UX31A (Full HD IPS in 13"), but looks like some things there don't work yet: https://help.ubuntu.com/community/AsusZenbookPrime