When buying a computer, there's always another big thing, whether its a new chip, graphics card, or OS around the corner. What you need to ask yourself is what you need the laptop for. If you are doing web surfing, Office stuff, Facebook, Skype, and/or e-mail, a core 2 Duo or i5/i7 mobile chip will suffice. Sure Haswell will be faster and probably use less power. But they are going to charge a premium for it, just like they did for the i7 chips when they first came out. Add to that the potential for problems with a new chip and you are probably better off buying an i5 or i7 system. If the prices hold true to form, you will probably find a better deal in January or February just before they switch to a new series of chips and no one has money for anything so they slash prices.
I'd like an ultrabook as well as a lot of the world. But manufacturers have priced them at a level where they are only affordable to those willing to pay a premium for portability. I'd probably go with a 13" or 14" regular laptop instead.