Looking forward to the payout, either way. :)

Now your splitting hairs. If you haven't noticed, there is a drive to make OS X more iOS-like. Let's see what happens after Mountain Lion, if it is iOS that they call the next release of OS X I am still right. :)

I bet a shot of good scotch and a pint of Guinness on my prediction. Will you bet against me?

Apple has no problem pissing off/on customers; so if that is the linchpin of your argument you might want to pass on my bet.

Don't get me wrong, I completely agree. This is a mistake.

I love my MacBook Pro; but I fear that in another generation or two I'm going to have to give them up because I don't like where Apple is taking their OS.

It was ALSO a mistake to for the OP to which I was responding to blame Tim Cook for this descent from walled garden to sealed garden.

"you simply won't be able to run X11 apps on Mac OS X any more"

This is patently false. Apple is no longer supporting X11, but they are recommending that people install an open source X11 for OS X called XQuartz. So, you will be able to run X11 apps in Mountain Lion.

http://www.macrumors.com/2012/02/17/apple-removes-x11-in-os-x-mountain-lion-shifts-support-to-open-source-xquartz/
http://xquartz.macosforge.org/trac/wiki

Don't lay this on Tim Cook. This was Steve Jobs's plan; Tim is just carrying on with it.

Here's my prediction: The version of OS X that comes after Mountain Lion will only let you install applications/software from the App Store. Again, Steve's plan; not Tim's.

If I may, I'd like to address a couple of assumptions in your post:

"I can make an image of the drive, then wipe the machine, and restore it back to its former state if I ever have to return it."
You can't guarantee this. I am on the security team at my company. When a person is being let go they called into a meeting and someone collects their laptop or desktop while they are in the meeting. In only one case have we allowed someone to access their system after it was collected, and that was under supervised conditions. We pull the laptop hard drive, label it, and shelve it. If that were your drive, we could have your personal information sitting on a shelf for years, waiting for someone to access it. While this didn't happen to me, a friend of mine was asked to peruse the hard drive of a terminated employee, and what she found led to criminal charges being filed against the ex employee. Not saying you would do anything illegal, but never put yourself in a situation where someone else has unlimited and unrestricted access to your personal data.

Also, this could be a violation of company policy and could be grounds for disciplinary action.

"I can use portable apps off a usb key and browse in private mode."
Yes, you can, but that doesn't mean you can bypass any monitoring or filtering software installed on the machine.

"Are there any other precautions I could or should take?"
It's just not worth the hassle, and potential employment repercussions, to modify your company owned system. I have two laptops that go with me everywhere. One is my work laptop, the other is my personal laptop. I keep both realms deliberately separated. Buy yourself a Macbook Air, or other maybe just a tablet since you mostly indicate you are browsing. Keep your work and personal life separate.

This 'article' is clearly written by someone who's never had to even think about securing an office network. He's right, I don't want users plugging personal laptops into the network, or checking company email on smart phones that aren't PIN locked, or installing TeamViewer/GoToMyPC on their systems, or countless other 'toys' that put the company at risk for a little extra convenience. What he fails to mention is that circumventing these policies in a corporate environment can be cause for dismissal. If he worked at my company, his badge would already be revoked and his accounts locked out.

Flat out, this person is a threat to his employer, not a role model.

Yesterday's Slashdot, to be exact: http://it.slashdot.org/story/11/12/14/225204/the-four-fallacies-of-it-metrics

In theory, I prefer FreeBSD. I have been running it as my primary server OS for 16 years. I have 30+ VMs running it right now. At the time they were easy to spin up an configure for my friends for whom I provide hosting.

In reality, the nearly constant state of screwed up dependencies in the ports tree makes it pretty much impossible to keep those 30 systems up to date without serious amounts of manual prodding. Keeping PHP up to date alone has drained my will to keep running FreeBSD.

At my job I maintain several thousand CentOS boxes, via puppet. The ease of keeping these systems patched is like night and day compared to my mere 30 FreeBSD VMs.

The only things keeping me running FreeBSD are nostalgia and inertia. The next time I need to do major updates I plan on swapping them out for CentOS.