If you don’t like the default behavior in Mac OS X which paste text with its styles there is a way to fix it! I personally find it very annoying when I press command + V (⌘+V) and text is pasted with all the formatting from the original source. Suddenly my beautifully picked font in an email or an Evernote note is ruined. Email looks like a decorated Christmas tree.
Of course there are alternative combinations to ⌘ + V to Paste and Match style but they differ from application to application and hard to use even if you can remember them.
Go to you System Preferences, click on Keyboard Shortcuts, pick Application Shortcuts and add applications (or make an “All Applications” rule): http://cl.ly/image/2j0Y283a3W1N