Development/Programming

1. Windows

1.1. Dot Net (not actually a language technically but its a platform to develop windows apps)

1.2. C++

1.3. Ruby

2. MAC (OS X and iOS)

2.1. Objective C

2.2. Swift (recently launched by Apple)

3. Cross Platform Languages (Windows + Mac)

3.1. Actionscript (used for adobe air)

3.2. QT (not a language but framework in C++)

4. Web Development

4.1. PHP

4.2. Java

4.3. Python

4.4. Ruby