If you're not really a fan of the Macbook's current design, I would definitely wait to see if they make any changes to that. Otherwise I would said go for it and buy it now. But with Macworld not even a month away, wait and see what happens with the specs.
Macbook was updated 2 weeks after I got mine, I was pissed (I also had no idea that I should have searched it out first, It was my first Mac). But after I got to using it I've found that it still runs blazingly fast, and the Hard Drive still has 47 of it's original 111 GB empty after 8 months. I'm very happy with it, I say just get one now and forget about it.