Well, I don't have a macbook, but an iMac (nicknamed "Monolith") which was given to me by well-off relatives. It was purchased at macconnection.com, which is a decent site that sells mac products at lower prices than the Apple store, and they give you freebies with your computer purchase. Just make sure to fill out and send in the rebates though.
I'm pretty sure that whether it's a Mac or PC that you purchase, it'll still be a clean slate for you to start on and thus will be much much better than your old computer. Just try to do as much research as you can and, if possible, test out any models you're interested in.
In short, if you want to stick with what you're familiar with, then go with PC. If you feel like you need some Mac experience, then make the switch.