Well if you develop as part of a firm, or in a team, the question goes out to you.
When in this team enviroment, what is your role? For instance, there are three PHP Developers and one C# developer. My role generally speaking is to bridge the data between C# & PHP ( Soap and such etc ). As well as making API's for other's use, I don't spend much time on the front end actually making features and such...Can't be bothered with validation and such.
EDIT: I expand upon jQuery with plugins and such so I suppose that could be considered front end work.