mac for me tends to be for media (final cut, iphoto, etc.) and some games. Windows tends to be my programming and majority of games. If you want a good Mac but cheap price I would perfer the mac mini which can be quad core or duo core. The duo core one can be $500. I would not perfer the laptops they are way to over priced compared to some of their desktops.
The software of Mac looks nicer, much more user friendly and gives me less trouble tring to do stuff like partitioning a hardrive. But Mac does not hold a big market for games... but is growing from the mac app store. A lot of times artist, authors, and liberal arts people get macs because of their easy use. I am not saying mac's are perfect but tend to be more comfortable for people to use. On the other hand PC's tend to be harder to use, but have a lot more resources at hand such as Directx and opengl, where mac is only opengl (I believe) and have a much much much! better programming languages then mac... objective-C is a pain compared to visual BASIC (or in this case AGK). But that is my opinion
sov the game creator!