I think I would have an easier time solving the Israeli/Palestinian conflict than the Mac/IBM divide.

I own both. Most of my machines are PCs, but there is a 9 month old iMac sitting in my home office that I use regularly. My wife owns a newish (September) Sony PCG-4L. I have an older Sony PCG-TR3a. Both notebooks are micros. Both can fit and Steve Job's interdepartment envelope, but mine would clearly bulge the envelope a hair.

The class of machine we're talking about is aimed at the road warrior. It is designed to take a computer that gets the job done whereever you want to go. I would bet that most people who own such a machine, also have a desktop at home.

Looking back at our past usage, I just think that Apple has made a few too many compromises. First, most road warriors I know carry a DVD or two with them for hotels, layovers, etc. Each of those, however, would be a lost movie rental for Apple. Many new laptops even allow you to play your DVDs without booting your computer. Obviously, you can't do this with iTunes.

DVDs & CDs are still a method of data transfer. My wife will sometimes leave data with clients on CDs. More and more companies have stopped USB keys from working on their machines for security reasons, and you often don't want to stick your USB key in an untrusted machine for a variety of reasons.
Yes, you can "borrow" a drive, but that is easier said than done, particularly with a machine on a secured network.

I know you can also carry a superdrive with you. Detached things, however, often get left at home, particularly when you are trying to fit five days worth of clothing, a notebook, a paper file of some sort, and a personal luxury item or two into a brief case and one carry-on bag.

This machine maxes at 2 gigs. If you run Parallels on your Mac, 2 gigs is barely enough. I added 1 gig (to bring it to two) on my iMac and I'm not completely thrilled with the speed at which Parallels runs. Because of Windows activation issues, I have not tried Fusion or the newer emulator (Crossover).

Just my two cents