I like both Windows and Mac OS X, but I choose Mac OS X for my music and video editing, Garage Band, iMovie and iTunes, I like all of them quite a bit and use them often.
I still use Windows, and primarily support Windows in my IT / Help Desk job.
I like Microsoft Office, Word, Excel and Outlook on a Windows computer, if you will be using those quite a bit, you may want to consider a Windows based computer.
I have more difficulty in formatting documents in MS Word (and other applications such as Text Edit, and E-Mail) on the Mac, cannot get as many letters / numbers on a line etc. I can make more use of the page in MS Word on Windows. Formatting text is also easier in Windows. In Windows, hit the "Home" key on your keyboard and your cursor moves all the way to the left of the current line, press the "End" Button on the keyboard, your cursor goes to the end of the current line. Hit CTRL + Home, your cursor moves to the top left of the document, and press CTRL + End, your cursor is on the bottom left of the document.
I have spoken with other Mac users and they cannot provide me with a Mac equivalent to those. You can hit the Home button on a Mac keyboard and End, your cursor will be at the beginning and end of the document respectively.
There are virus considerations, reportedly Windows is more vulnerable, mostly (In my opinion, and many others, Google it) that since there are more Windows computers, they are a bigger target. Use care and learn safe browsing and not using peer to peer web sites will help your Internet experience on whatever platform you choose.
Other Considerations
If you get a Mac, you can still install Windows on it using Parallels, Mac's BootCamp, Oracle's Free VirtualBox etc. and boot between Windows and Mac. Bootcamp gives you the choice of which operating system to boot into, where VirtualBox and Parallels allow you to boot into Windows (or Linux) while still being in Mac, you can switch between the two, close out of Parallels or Virtual Box, and you are still in OS X.
Many other scenarios exist, hope you find this helpful and are happy with your choice. As you know you will likely lay out more money on a Mac.
:) Source(s): Experience with Mac OS 7.6 through OS X, Windows 3.1 through 8, Virtual Computing and Linux. Much web surfing, using of the Operating systems and study. This Blogger article was inspired by a Question on Yahoo Answers: Yahoo Answers Question