and you might also want to think where you will use your programs (that are more powerful - i.e. photoshop, video editing, or other stuff you do) most
Let's say you mostly work with those programs at home, and you are unlikely to do those on the go, where you will only need programs such as office or firefox, for note taking and surfing the net
Then you could get a combination of a desktop and a laptop (netbooks)
Since you'll definitely get a better value for money (power-wise, not portability ofcourse) from a desktop.
And netbooks for portability - costs probably 400 - 600 (depending on your needs, and linux/windows)
and since most programs are windows compatible anyway, there's really not much difference between windows and macs
Let's say photography programs - (apart from photoshop)
--
Adobe Lightroom,
Capture One, those are professional programs - windows compatible
Video editing - not so sure since I've never paid attention to that aspect
But like others said, macs a kinda overpriced just because it has a... 'creative' factor... which isn't entirely true anyway