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.
I currently am part of a two man team, that is my boss and I. I do a lot of the coding since he is always being pulled in various directions by upper management for no good reason. So basically what happens is we get permission from the top, make a plan and to it. We both are quite capable on every stage of development. We also maintain the many current systems we have.
We are looking for four to six more people for our development team, that's when more dynamics are going to take place. I'll be the help desk guy maintaining and fixing bugs as they come, my boss will stop coding and do management (this includes random crap form the execs) and the other guys will primarily be development (we have some huge plans).
I am currently part of a 4 man team, I do the following ... Linux Administrator, Server Administrator, Snr. PHP Developer, jQuery Developer,All Front End Layouts, Database Administrator, Python Developer, Django Developer and I think that's it...