[mothered]

It depends on your overall usability. A lot of times, It's not the OS that's the Issue, but more so the "user" behind the OS (due to carelessness, lack of training, awareness and safe practice).

For those who simply navigate via Facebook and nothing else, a good Internet Security Suite (along with some training and awareness of how to browse safely online), will suffice. If you're Into the hacking side of things, always have a "dedicated" system solely for that purpose and nothing else. If you have a home network (like myself), Isolate/segregate It from the network. I highly recommend Installing a VM (Virtual Machine) and use that as the Guest OS, thereby every task will be performed In It's Isolated environment, hence the Host system (physical machine on which the VM Is Installed) will remain untouched.

Keep your sensitive credentials (logins and the like) on another PC and ONLY login via that. For extra security, you can use a "Live CD" (example Linux) and login thereafter. Although It will not prevent MITM attacks, because It's "read-only", It will certainly protect against keyloggers, RATs, stealers etc and any malicious content looking to Install Itself on your PC.

There's too many to mention. As said, It depends on your computing habits and how you utilize your PC.