Seems silly to me to not include it still. on my powerbook i can remove the battery and take out my airport card. I heard somewhere that there was a little free space in macbooks.
In terms of portability you simply can't beat a built-in, always on cellular data connection. I'm busy! i don't want to worry if my phone is in the same room. I don't want to worry about making a call while i'm connected. I've tried the cingular/att connection and the difference between that and time warner cable in nyc is small enough for me to want to completely switch over.
note to apple: i will buy a macbook as soon as this is available and not a day sooner.