If you can wait, you really want a Haswell device
The problem with Windows 8 Pc's at the moment are they're not very good tablets and not very good laptops. Bare in mind their in their infancy though, the next itineration will be better and Haswell will give a big boost in battery life. If you can hold off, then please do so
If you really want a windows device, and you can make do without the need for certain features (such as macro support), you might want to look at the Windows Surface RT. Good price, MS office bundled in with the device, and decentish battery life. You can pick them up at John Lewis, or with a decent discount on e bay.
If it was my money, I'd wait for Haswell. Or at least see what the new AMD chips with their 8w power consumption has to offer. Hold off till the summer, you won't regret it.