Question Thursday: Which book do you wish had a sequel?

I love immersing myself in an great series of books.  Sometimes it is hard to settle for a stand-alone novel when you want to devour an absorbing series of three or thirteen.  Obviously, there are lots of awesome stand-alone novels that are perfect exactly as they are, and not every book series is made of excellence from start to finish.  But I love the torturous suspense of awaiting a sequel, and I love reading more about characters that I adore.  :)


Are there any books you wish had been the first in a series rather than stand-alone novels?  One book that immediately comes to mind for me is Robin McKinley's Sunshine.  Rae and Constantine's world seemed richly prepared for continuing adventures, and I wasn't completely ready to close the book on their story as I turned the final pages of that novel.  So I was disappointed to learn that Sunshine would never have a sequel.  What book (or books) do you wish had a sequel?