Amy
What types of applications, (other than MS Office), do you feel you need for productivity in your occupational field? I know that you have the ability to do word processing and presentations with OS X with a variety of applications, including PowerPoint, but I'm not sure what other applications you use fairly often.
From an OS perspective, Mac OS and MS are not all that different, although there is a little learning curve to learn the way Mac OS is implemented. But for someone with a fair understanding of basic personal computers, the transition is not that hard. Macs will tend to last a little longer than PC based systems. The operating system will be far less complicated to maintain and update. In other words, your use of your computer will focus on productivity or personal use... not maintenance of the computer or it's OS system. Plus you have a decent amount of software tools included with your system. The old stigma was that Macs were primarily for specific use or non mainstream applications, but that has not been the case since their move to Intel processors and the ability to power crunch business related applications more easily. In the education community, Macs have a pretty good representation, and that is growing now in the business side of the community with the ability to run business related software better, now that you can run Windows based applications in Parallel or VM, (though Mac users do pray for the day when we are not forced to have to put the Microsoft garbage in our computers).
I've used Microsoft products since the days of MS DOS until Microsoft decided to come out with Vista and Server 2003. The decision to switch for me was an easy one, to be honest.