Sometimes, using virtualbox or VMWare doesn't work, due to 3d driver support.
To transfer back, what I found worked best was to just pull each event out of iPhoto in its own folder. I did it manually over a few days. Yes, it sucked, but Apple's a very, very, walled garden...
I guess I spared myself some of that when I came from PC to Mac. I had been using syncback (freeware) to copy my stuff to a network drive nightly (kind of like using time machine editor.app to only let time machine run at 2am.) When I was ready to "make the switch" I merely powered off my PC and gave it to one of the kids, powered on my new (at the time) Macbook and copied all my stuff down from the network drive. Done. For a while I allowed iPhoto to make copies of stuff in iPhoto Library but later realized it was a trap. All of my media, whether movies, music or photos lives on network drives in formats that are not exclusively Apple centric. This is not because I mind the walled garden. It is because it's my stuff and I would rather manage it myself.
For now, my PIM data (contacts, calendar, memos and todos) lives in MobileMe. I recently sprung for a $5 "contacts cleaner" app that went through and found problems with 2/3 of my data. Phone numbers had become emails and emails had become phone numbers. Zip codes had become phone numbers and comments had become phone numbers. This was caused by issues with Palm Desktop, then Mark/Space Missing Sync for BB OS, then BB Desktop Manager and of course iSync getting into cat fights with the aforementioned non-Apple products. Now my contacts are cleaned up and backed up. I am considering importing them into google contacts so I have "another backup" of my stuff.
If I decided to "move on" to Windows or Linux, I would not be at the mercy of any proprietary Apple containers for my data. The fact that I'm happy and never intend to move on has nothing to do with keeping my stuff "portable" as I think this is simply a good computing practice. I took the pictures, ripped the cd's, entered the data and I'll be hornswaggled if I'll let any company, even Apple, "sell it back to me" or charge me rental for my own stuff. That being said, I freely choose to pony up my MobileMe subscription once a year because I like the seamless way it works across my Mac, iPad and iPhone but the underlying data remains accessible to me outside of Apple's ecosystem any time I want it.
I'm thinking that the next logical step for me is to sign up for one of those internet based backup services. I'll put all my stuff on carbonite or crashplan's cloud and it really won't matter whether I'm pulling it back down using OS X, Windows, Linux or even a web browser.
BTW, I've heard the same thing about drive support for Apple hardware causing problems for Windows installs in either bootcamp or vmware. I use Crossover to run the few dozen windows programs that can run under "Wine" and to me that is better than sacrificing large swaths of my hard drive for a "windows partition" I would only rarely use.
