I agree with taseal. I had started a few threads asking the same questions. Particularly, I was thinking about waiting for the Core2Duo's for the MacBooks.
I went ahead and bought a few days ago. A friend and I were talking, and we talked about the differences between the MacBooks and the MacBooks pros. In our opinion's, there was very little differentiating the two, save the dedicated video card in the MacBook Pro's. That little difference currently costs you almost a thousand dollars or more. Due to this, I wouldn't imagine that the MacBook Pro's would be selling very well at all right now.
Fast forward to the release of the Core2Duo chips, and I see this as a perfect way for Apple to differentiate the MacBook Pro from the MacBooks by immediately updating this line with the new chips and finally being able to see some price justification for this model.
The MacBooks will get the updates too I'm sure, but I certainly wouldn't count on it being this year.