[KungFuNav]

Actually, thinking it through, it might be nice if Calibre could use something like:

Xanth [21,37]

instead to indicate the book number and number of books, so the series title remained alphabetic, and the number of books could be updated automatically (i.e. if one book has the number of books, the rest could automatically use the same value, and an amendment to the number to one could affect them all).

That way if you import a new series it's not such a big deal if the number of books isn't there... or perhaps a plugin could automatically add the total number of books (if it recognised the series name) from a website that held that sort of info.

It is nice to know at a glance how many books are in a series, I could add a custom column to hold the info I suppose, but would rather not customise the out of the box Calibre if I can help it.