I said this earlier and I will say it again, it is 10000000% based on your personal budget. If you can afford to get a good Mac and are serious about design, do it. If you cannot afford one it's not a huge problem to use a PC, specially fi you only do AI/PS design. If you do more advanced media editing or do development of any kind, using a Unix based system makes an incredible difference and is worth the price *if you can afford it.*
Studios with 100k budget on design department for hardware will never have PC's, that is a fact. This is not just because it has an Apple on it, it is because Adobe products are designed for Mac OS first, Mac's have Unix based OS which is nearly mandatory for development purposes, and come with the highest quality displays on the market.
For your own personal use however, unless you are serious about design, and can take it off as a business expense or are able to justify the cost per productivity gain, just build a PC and save yourself the money. After you deal with the headaches along the way it will become clear why Mac is the industry standard for design, and why Apple is allowed to charge so much.
I CANNOT stress enough, if you get a Mac, it is for business, it is for design, it is for media, it is for development, it is a work machine. If you need to have casual/gaming use as well as minor design needs, just build a PC and save the thousands that you need to put to use on other things in your life. BUDGET is important for nearly everyone, and if budget is not important for you, you probably already knew you were getting a Mac.