In terms of security, Linux is much stronger then Microsoft "malware wise".. Hackability, now this is a different story, as there are those that know Linux quite well and how to exploit it "this is of course unless you are a linux Pro", and know how to lock it down so tight you can not operate it, let alone anyone else
Seriously though, Linux is definitely a great platform. My only issue with it is the application support differences between different distros.
There are tons of applications to replace windows ones, but i have found, some may work great on one distro, but not on another. There are so many choices in the linux world, that average users get over whelmed, and tend to lean back towards windows.
Driver support is definitely gotten better over time, but still, many times you are using generic drivers in Linux, and missing features you would normally get on windows with the manufacture drivers "which may or may not have a work around in linux". Newer machines may have issues with this, until patches get released at a later date in the kernels.
There are pluses and minuses for both OS platforms.
One thing keeping me leaning towards windows right now is gaming, and as stated, this problem is mostly due to companies then it is linux, for top feature titles not being compatible with Linux.