Don't forget the extra GP registers added by the amd64/emt64 extensions. Those are worth the upgrade by themselves.

However, Apple isn't advertising the 64-bit angle for their laptops and iMacs...

See, that's the thing. Apple IS advertising the iMac as 64 bit. Just not the 'books.

Cast your gaze on the ultimate eye-opening experience: the new faster, bigger, and brighter iMacs. Starting at just $999, the most personal of personal computers comes out packing a powerful punch. That’s thanks to the new 64-bit Intel Core 2 Duo processor, you’ll find in each and every new iMac.

source

I'd missed that one. Mostly it sounds like they include that in order to prevent negative comparisons against the PowerPC G5s they were using in the iMac previously. The laptops never had a 64-bit capable processor, and since they can't really take much advantage of that feature (in terms of memory address space etc) they just don't bother.

An odd point, to be sure. Frankly, many parts of the industry seem to be pushing the "64-bit" angle without much reason. Reminds me of the old Sega/Nintendo console war days in a way.

What matters to people is if "it runs stuff faster".