If you actually wanna work on it, you want a business notebook. Carrying it with you everyday will require a strong chassis, long battery life and light weight. I'd recommend either a Macbook Air if it has to be the ultra of an ultrabook, otherwise look for a Thinkpad. The new Intel Broadwell models came out recently, so the Haswell generation will drop in price. Thinkpad X240 would be worth a view if an 12" screen is enough for you, otherwise have a look on the T440s. I think both have two batteries (at least the T440s does), one built in (still removable) and one removable. Can get you 10 hours of browsing / office work easily while still being strong and portable. They're not as pretty as a Macbook and that wannabe Mac ultrabooks, the newer models are fairly nice though and that keyboard is one of the best (if not the best) out there.