Have slacked off watching Battlestar of late, but I couldn't imagine it lasting much longer. Not that it wasn't quality (it indeed is), but a show like that is limited in it's plot lines.
3-4 seasons of good work is nothing to sneeze at.
Now, if they do a spin-off with No. 6, Starbuck or both of them trying to make it through life in a cyborg-human lesbian relationship, that would be something to watch.