From what i have heard for multimedia editing a mac is far superior to a pc- there is of course the dual boot option mentioned above as well if you can't give up pc completely.
Personally, i made the switch to mac about three years ago- started with a mac mini in addition to a pc and now i just have an ibook g4.
I prefer the mac for a lot of reasons, but admittedly it did take a bit of getting used to. There is no reason why you cannot use the mac for other things as well (email, browsing etc) although the gaming will be a weakness.
Personally, i would go for the mac
you never know... you might like it
