Whatever you do, do NOT get vista. XP is way better!
I had to write a term paper for school that was five pages long. I saved the paper on word a bunch of times. First, I could not even find the file ANYWHERE on my computer. After searching for almost half a hour, I open it up to find it's encrypted or something. It took me another good 20 minutes to remove all the added encryptions. For example, if I added a tab, instead of a tab, it would say /tab, /-enter, whatever.
Everytime I wanted to save, I would have to attach the paper to an email draft.
I'm sooo glad I switched back to XP.
As for macs, my friend got a macbook pro less then a week ago. From when I used it, it was pretty cool. I really didn't see the difference between a MAC and a PC. Besides, I think MACS are more for like artists, and professional graphics and all that. I think PC's are better for word documents, business and such.
I also compared my friends macbook pro to my friends dell inspiron, and the pro weighed ALOT more than the inspiron, even though the inspiron was bulkier. Also, the macbook pro's touchpad was bigger than the inspiron. I didn't find it useful though. You had to either press really hard anywhere on the touchpad to click, or go to the bottom left corner since there were no buttons.
Obviously, this is nothing really to decide on whether or not to get a PC or MAC, but just basic stuff you may not like about either; or an inconvenience.