Unfortunately these types of questions always bring out answers that are based on perception and generalities that paint very inaccurate pictures of both Windows and OS X. Let me bring some objective facts to bear that may help as most of what I've seen in the answers so far is inaccurate at best.
Neither Macs nor PCs are specifically geared towards any kind of work. So the claim that Macs are good for design and video editing is false. It's the software that makes a system good for a particular purpose. Yes, Macs ship with better applications (iLife) that make video editing easy, but if you're serious about the topic then either platform will due since you'll have to buy better software anyhow.
If you're running Visual Studio then you need Windows to do that. That's a fact, but that doesn't mean you need a PC. Visual Studio isn't exactly a big resource hog, so you can either use Bootcamp to run Windows on your Mac (no speed issues and no driver issues - despite what others have said). Bootcamp includes all of the drivers for Windows that you need to run it on Mac hardware. That's part of its purpose.
You can also buy and install Parallels or VMWare Fusion to run Windows inside a virtual machine. Some performance slowdown here, but for Visual Studio it's not a big deal.
PC Magazine actually rated the MacBook Pro as the best laptop for running Windows Vista for a couple months straight. Obviously as new PCs come out, this award gets shifted around to other vendors, but rest assured Macs are great machines for running Windows.
The biggest misconception is that Macs are just more expensive. Well, you could say that, but the fact is that buying a Mac is like buying a car that's fully loaded. It comes with a lot of premium features that are pre-configured. And when you just compare "a PC" to "a Mac" it certainly seems as though Macs are more expensive, but the truth is that the PC is typically configured to be less expensive. That being said, there isn't really an option to buy a slimmed down Mac configuration so your price points will start higher, but that doesn't mean you're just paying more for no reason. You're getting more too. Whether what you get is valuable to you or not is a personal choice.
Now those are the objective points of fact. Here's my subjective opinion. Macs are my preference. To me they offer more versatility. I can and do run certain Windows only apps (Visual Studio included) and with my Mac I can do this as well as run my favorite production apps that are Mac only such as Final Cut Pro. I can't get that kind of versatility if I choose a PC.
Hope that helps. Best of luck in whatever you decide.