Unless you're already into macs, I'd say to look into a barebones kit. Apples $1500 desktop computers can run i3 processors, while a well loaded barebones can cost under $1500 and have better specs all around.
I understand the mac thing, looking into a refurb mac myself, but just make sure you know what you're buying -- I am looking into a $1500 barebones kit complete with windows 7 premium, an intel i7 processor 950, a good graphics card, and good amount of memory, a good motherboard, and a good monitor --And you can always upgrade with barebones - good luck doing that with your mac.
You can also get barebones laptops, too.
But I would say that unless you need the portability of a laptop then stick to a desktop. Better all the way around, but of course the most important, portability, is a no.
Weight your options and make an influenced decision. A forum member here helped me build an awesome machine barebones, so PM for his name if you're interested.