For computers, for most consumers, you only see Windows 7 or 8, and Max OS X. Some people use different versions of Linux (Ubuntu, Fedora, CentOS, Debian, etc). Another popular OS (I believe it's run by Oracle, the people who made Java) is Solaris. There's ChromeOS, and many others.
For phones, the most common ones are iOS (great variety, runs perfectly almost always, incredibly secure) Android (arguably better variety, often has issues, not secure, hugely customizable and expandable), Windows Mobile, Ubuntu Mobile, Blackberry, and so forth.