1. Apple's professional-level notebook is the MacBook Pro. The Mac Pro is a completely different machine, but I think you already know that.
2. I've never heard that all updates on Macs can be installed without restarting the computer. Some updates can be, but critical updates that affect specific applications or system files will require you to reboot the Mac in order for them to take effect. Windows works the same way, last time I checked.
3. As mrmacfixit has already pointed out, .Mac (pronounced Dot Mac) is the subscription service that you must pay for in order to have an email address/Apple ID ending with @mac dot com. It works very well with iChat and other programs that have integrated .Mac support, like the current versions of iPhoto and iMovie, but it is not required to take full advantage of other programs. I have both a .Mac subscription and a regular AIM username, and both can use video conference with each other in iChat. Trust me, it works, and there's no reason why it shouldn't. You do not need it for iChat video conferencing.
4. "You cannot use the webcam for other sites so what is the point of having it. Also is there a webcam out there some where you can use on an apple machine that allows you to see other sites?"
I believe you are asking if the built-in iSight camera will work with web-based video applications and the like. Compatibility probably depends on the site/service. The camera itself cannot be blamed for it. If you are looking for an external webcam, just look for one that clearly states that it has Mac compatibility. Or just find a used FireWire iSight camera on eBay (those are the old, external iSight models and are no longer in production).
5. The learning curb depends on the user. You'll find many differences between OS X and Windows. Many people believe that OS X is easier because it has been developed with a more user-friendly interface. Usually, it is easier to use once you figure out where everything is. For many basic tasks, it only takes a few minutes to get the hang of it. Sure you have to get used to it. It's not like Apple thinks the average person will automatically know how to adapt to the Mac OS.
What has Apple not pointed out? Their manuals are very straight-forward and they offer tutorials at the Apple Stores should anyone need them. Apple doesn't have "anything coming", as you put it. They've done a great job with the Macintosh platform over the years. It's not like they are hiding information from their users. Apple tells you almost everything you need to know, and if you don't know how to use their products, ask. Their customer support is pretty good and Apple has been known to treat its customers well, hence the strong band of Apple loyalists. I've had my share of experiences with Apple support, and they usually did a great job of helping me out.
-BMF
I've been using a MacBook Pro for about a year now and it is by far the best laptop I've ever used. It's solid, works when I need it, and is a great tool to have.