Wait a month or two.
The latest gen of intel processors (Haswell) are coming online now in Laptops - and whilst only a wee bit faster they give 50-100% greater battery life - so are well worth waiting for... They are in some of the latest macs - (I think the 13" air is one) but not all at the moment.
But if you can't wait, PCWankers presently have £100 cash back on any PC/Notebook over £500... (including apple stuff)