Simple answer, thats not meant to be patronising - depends what you want to use a computer for. Personally, because of what is more common in the workplace, ideally a PC and also because of compatability of applications, although as time goes by, more and more programs are PC and Mac compatible.
One is neither better than the other. Macs have their uses and PCs have their uses. Both also have their shortcomings. I use both. Macintosh machines are a lot more stable machines than PC's and are specifically designed for the graphic industry. Major graphic/web/multimedia/music software is designed for use on Macs. Most, if not all multimedia companies use Macs. The problem with Macs are quite minimal. They do tend to crash but not as often as Windows-based PCs. Downloading free software for Macintosh machines is increasing daily. PCs, on the other hand are great for databases, spreadsheets, and suchlike business related stuff. They are also a lot more games for PCs. Buying software for PCs is also a lot cheaper. But PCs have a tendency for crashing and graphic software is quite fiddly and cumbersome. Also they are not as user-friendly as Macintosh machines. So all in all, you decide which machine is better for YOU by what you will be using it for.
Like one of the other answers said, it depends what you want to use it for. Macs are, in my opinion, more intuitive and easier to use. The new ones also look much better in the corner of your room. They can be more expensive, though, and most software will come out later for them. Also, if you're very new to computers, beware that if you buy a Mac, most of your PC-owning friends won't be able to help you if anything goes wrong or "lend" you software...
If you've never used a computer before you'll find a Mac much easier to get to grips with and more stable than a PC. Because Apple make the machine and the operating system they are less prone to incompatability. In the PC market, Microsoft makes the operating system and there are many different manufacturers making the hardware. In terms of which is best for your needs, however: Graphics, video and music - go Mac. Games and business applications - go PC.