Mac and Windows are essentially two different systems with different workflows. Unless the design is an issue, choosing one over the other should ultimately come down to which workflow you prefer.
There is alot of myths and bullsh*t going around in this thread though, so i thought I'd comment on some.
First of all: Mac is just as vulnerable to Viruses/worms/rootkits/malware as Windows are
The difference is that there exists more of those for Windows 7, and therefore it's easier to get "trapped" if you aren't an experienced user.
That, however, doesn't mean that you are more vulnerable to viruses as a Windows user just because there exists more of them for Windows. As always it comes down to good security practice, like keeping your system updated, using a secure browser (read: not Internet Explorer 8) and verifying the software you run. Be critical of the source (both the place/person you got it FROM, but also the person/group/company that wrote it), as be on the lookout for suspicious behavior. Mac has viruses too, and in fact a virus/malware-software was recently discovered that attacks OS X 10.6 and 10.7.
I'm currently running a virus and malware-free Windows 7 installation, and this is 100% entirely based on me knowing what I'm doing and what software I'm running. I don't even use an anti-virus anymore (although for less experienced users, I'd recommend it).
Also, don't listen to people claiming that anti-virus software slows your computer down. If you are running a modern computer, ANY slowdown caused by anti-virus are completely negligible, and you won't be able to feel it in your day-to-day use of the computer.
Now, in regards to the OS itself, some people here have mentioned that the Mac OS is way better optimized than Windows is. This is partially true, and Mac does outperform Windows at certain tasks. Audio-handling is one of them (although Windows does absolutely FINE there too). For people who are digital DJ's - which I am - this might be an important consideration, although i have tuned my Windows PC for DJ'ing and it runs like a dream so i don't complain.
In addition, OS X also has smarter RAM and resource-allocation for the interface than Windows 7, which gives a more responsive system even when using a HDD over an SSD. However, Windows has made major strives in that area too, and Windows 8 - even though i despise most of the changes and will continue using Windows 7 for the time being - have further improved this compared to Windows 7, meaning that Windows is basically as fast as Mac is now if you decide to upgrade to Windows 8.
Now for the more personal stuff, I personally don't like OS X for several reason:
- I think the multi-tasking experience is vastly inferior compared to a properly configured Windows-setup (which might require additional software, but ultimately what matters to me is which i can work the fastest on)
- I consider the keyboard-shortcuts and keyboard layout vastly inferior
- The Window-handling for quickly resizing and scaling Windows, as well as how OS X handles full-screen is also vastly inferior IMO
- The "corner" behavior of OS X (and also Windows 8 for that matter) can be intrusive when using a multi-monitor setup (which i do)
- I don't like the fact that the system is more locked down than Windows is.
- More third-party software for Windows.
- Gaming is still vastly ahead in Windows.
In fact the only thing i think Windows is missing compared to OS X for multi-tasking is Mission Control, but there actually exists software for Windows that enables that just fine and i use that (the multi-desktop feature is never one i found useful for me, but some people do and it can be emulated in Windows too). Result is that with my Windows machine, i get a much faster multitasking workflow than i do with a Mac.
If you like the Mac workflow and design, though, then by all means, go for it.
Capcha: The end is near <--- Oh you bastards!