It's tough because you don't want the formatting...until you. If I'm editing text that has a few bolded words I'd be immediately annoyed if the pasted text didn't have the bolded instances.
I'd then suggest that formatting that always conveys meaning (bold, italics, etc) should be copy/pasted.
On the other hand, formatting that often doesn't convey meaning (font face, foreground color, background color, shadows, etc) should not be copied by default.
A three-way option to system-wide (and per application) configure the behavior for control/command + x/c/v would be nice:
* smart copy/paste (what I just described) as the default
* copy/paste as plain text
* copy/paste with full formatting
I'd then suggest that formatting that always conveys meaning (bold, italics, etc) should be copy/pasted.
On the other hand, formatting that often doesn't convey meaning (font face, foreground color, background color, shadows, etc) should not be copied by default.
A three-way option to system-wide (and per application) configure the behavior for control/command + x/c/v would be nice: