I don't have a Macbook - and don't usually carry a laptop with me. (my dell stinks)
BUT - I DO have a North Face "Surge" bag - it's got a nice padded / semi-waterproofed section made just for a laptop, about the size of a 17" Macbook Pro -- I think it's trying to tell me something.
It's a very nice and comfortable bag - in spite of me being a Big guy. (which, makes many backpacks uncomfortable)
Also has a padded easy access pocket for your cell and MP3 (in my case iPhone) with a Cut Out slot for your headphones, and a clip for them on the straps. Cool idea, IMO.
My only issue with it - is it almost has too MANY pockets and dividers - I sometimes have to search out my keys... If I just used the same one habitually - this would be a non issue.
Man, I DIG that snot-green color. Where the hell was that when I bought my black one?
She's a tad pricy considering it's a day pack - but its built like a brick @($*house.
Linky:
http://www.ems.com/catalog/product_...older_id=2534374302876285&bmUID=1195465599248
Picture: