I have to disagree on the everyone loves a Mac thing. I hate them. I've worked with them since they first hit the market and still hate them. The Mac O/S totally frustrates me. I use "the fuit" (Apples) when forced (usually by some school because they love touchy feely things). Apples have always been graphic friendly and schools like their pretty pictures.
Cost is always a consideration. IMHO they are way overpriced. I think anyone who buys anything electronic should treat it just as they would a sewing machine purchase (test drive!!!). Find out about warranty service. Are you going to be charged for upgrades to your O/S? Peripherals, what do they cost? Don't forget there are things out there that just will not work with an Apple. Look at what you already own. Will it be compatible or do you have to totally upgrade everything (printers, backup storage drives, etc). All of that is important to remember.
I'm sure I have really made people mad with this post so I'm going to get back to my data now. This is kind of like getting into a discussion with someone who uses a Bernina about the best sewing machine to use.