Craig Hockenberry over at furbo.org explains how to set Paste and Match Style as the default option for ⌘V by setting a keyboard shortcut, overriding the default behaviour when pasting from the clipboard.
It’s a great solution and keeps the familiar keyboard shortcut, though it does have one caveat:
After you’ve made this change, you might find that the keyboard shortcut sometimes doesn’t work. The one that gets me the most is when I try to ⌘V in the “To:” field while composing a message in Mail. When you try to use the shortcut, you’ll hear a beep because the control doesn’t accept styled text and Paste and Match Style is disabled. When this happens, it’s easy enough to right-click and use the context menu or select Paste from the menu bar.
I’d used this keyboard shortcut for a while but this issue cropped up far too often for it not to be an inconvenience. Instead, I have a TextExpander snippet that just contains %clipboard, with the abbreviation `v.
I’m always using this snippet whenever I’m pasting text but, for anything else, I revert back to ⌘V. It’s not a better solution than setting a keyboard shortcut, but it may be a more useful one if you’re mostly handling text in the clipboard.