First weekend I had the XFire i bought the same cupholder pictured above and a set of valve stem caps (it was missing a few). The cupholder was cheap at Auto Zone. Works pretty darn well, and I almost always drive alone so it isn't a problem that it takes up passenger seat real estate. Also, when I do have a passenger it stows almost completely under the passenger seat, far enough that it isn't in the way of their legs/feet.

I like the look of it mounted between the seats but that seems like a really awkward angle.