Why do smart people still use windows?
I really mean it!
Most people here should know how insecure windows is compared to osx and linux distros.
Sure osx is more expensive but don't you think it's well worth it?
Windows has more software available to it. I can give you an example: NI Labview is only available for Windows (AFAIN), for more average users, mmm... games (wider range), office (there are clones, but nothing is easier to use nor has the same functionality), etc.
Maybe you could run software through PlayOnLinux or using VMs, but the performance is not even close to running them natively.
Buying a Mac is simply not affordable in some countries (I think mine is one of those), unless you get a huge paycheck every month.
Software is a valid point. You need to buy parallels too to run everything.
The price of hardware I think it's not a valid point because if you compare macs with windows top hardware (it's the only fair comparison) you'll see the price will match.
You should look into free (as in freedom) operating systems.
Someone should look into this and make an user-friendly package and of course charge a fair price for it.