For the casual user or student.. I agree, 32 or 64 doesn't matter. For people that do more than editing 1 page documents.. 64 bit really helps.. how much does it help? I don't have the exact data on that but from my first hand usage.. the real world difference b/w 32 and 64 seems great.
I have 64bit Office on my Thinkpad and experience a noticeable increase in productivity. Also, all the programs load in less than 0.5 seconds.. I've never seen anything like it.
For example.. I use Office to edit projects in powerpoint, word and excel that are sometimes close to a thousand pages long, I can move through and edit them much easier than I ever did before.. 64 bit handles it all like cake. There is virtually zero lag or load time with any size document, you feel like your working with 1 or 2 pages when it's actually in the hundreds.
Why would you want 32bit if your OS can run 64bit? seems like a waste to me..
Anyways, most serious office or business users will have windows. not to mention large corporations that value every second of time in the day.
edit: i forgot to mention again how terrible the office icons look in mac and the overall layout of the programs is bad for productivity.. no offense to anyone, but this is just another good example showing the target market for macs.