I use Mac cause I work in Graphic Design and it's industry standard. Plus I grew up using Macs, been using them for about 9 or 10 years now so its what I stick to. It has a better range of apps for the type of stuff I need to do as well. I do a little gaming on it like Minecraft and a bit of portal but nothing serious so its okay for that as well. If you wanna game more seriously though, obviously PC is the way to go. Also if you do development, programming that type of stuff- PC can be pretty good too aside from stuff like Web Development which Mac is fine for. I do run Windows 7 on one of my macs for if I need to do specific things. Works fine for me.
I think the PC vs Mac debate has no true answer, it depends on the person and their needs.