I just made the switch to Mac a few months ago. The reason I got a Mac is because it was the only sub 3 pound, 11 inch screen laptop I could find
I suspect I am coming from a different place than you *grin* as I am a control freak about my computer. I configure my browser to not store history or cookies. I reinstall a clean version of Windows. I try to use free (and open source if possible) software if available - Mediamonkey instead of Itunes, Picasa for photos, Gimp instead of Photoshop. I manage my files in my file system myself. I don't let other people mess around with my computer and therefore I very very rarely get viruses.
Macs are not meant for people who want to control their computer. The Mac environment/user interface controls everything for you to give you a seamless experience. Your Iphone, Itunes and Iphoto will all play nicely together. However, you will have very little control of your files - ex: photos in iphoto are just stored in a gigantic file and you cannot browse through the folders outside of the program.
Here are the issues I ran into when moving to Mac:
The key shortcuts are all different and the control key is in a different place (now I am used to it)
If you buy a book from iBooks, you can't read it on your Mac, only on a portable device like an iphone or ipad.
When you copy a directory on top of another directory with the same name, instead of merging the contents of the two directories, you lose the contents of the target directory.
I had an external hard drive where I stored a lot of my data in NTFS format that I couldn't read/write to reliably with my Mac. I needed to be able to read/write to my external drive from both Windows and Mac computers. I ended up reformatting my drive in exFAT format and then putting the data back on to achieve this.
Things that are nice about the Mac:
Being able to do whatever I want from a unix prompt - run perl scripts to automate tasks such as renaming files.
Trackpad gestures
Installing/uninstalling applications is MUCH nicer than Windows as you just drag/drop.
If you already love the user interface, I think you will love having a Mac. I would recommend a Mac to anyone who doesn't want to spend time "maintaining" their computer, which is really about 99% of the population. I'm neutral on my Mac - in the end I (and you) can get work done on any modern computer - it's just a matter of your priorities re: interface, specs and form factor.