I recommend someone who knows very little about computer to go the mac rout. Initial investment in a mac is high but it is worth not having the stress of dealing with malware and other problems. Plus, a mac has the cool and wow factor and a beautiful body. Apple controls what hardware they put into the mac and this helps eliminate many hardware issues. When you think about a Mac, you think about the package, the operating system, and the style put together.
I do not recommend a beginner to use a PC (or just Windows) to do important tasks such as doing banking or online shopping. Beginners are most easily fooled by email attachments, and malware pretending to be virus scanner software. Many of them did fall for these and did pay. Your chance with a Mac of having this problem is almost zero. A beginner with a Windows machine is just bad news.
Intermediate users and gamers may use Windows knowing that they can always restore the hard drive to factory default. Most Windows laptop these days come with a factory restore partition so that you can restore your computer to the way it was when you first bought it. Just remember to back up your important documents and files before doing the restore. I often use the restore partition because it is much much faster than finding a problem and removing it. Still, these people must be very careful. Software that works to steal your bank account are not necessary visible. You should buy security software.
Then there are those who have a mac and they installed Windows, Mac OS X, and Linux on it. I personally find GNOME on Linux extremely easy to use although for beginners, they won't know how to get flash, mp3, java, DVD video support on their Linux.
