I wouldn't pick skinning, since it can be mapped to a shortcut
so one of your other characters can have it.

But it is a tricky choice,
I guess you have to decide if you want a profession that will benefit your Pally as a tank,
or a gathering profession.

Correct me if I'm wrong,
but I believe that using cartographer on all the characters in your team will allow you to share information between them,
when new nodes are mined/gathered.
So in that respect, with a bit of patience, all nodes would eventually show up on you main's screen.