I had a graphire1, and sold it because i could buy a second-hand Intuos 8x10 inch or so.
my impressions are that you do not really get a visible
diff between both sensitivities, and that it is rare that you need a surface larger than the graphire one. An exception may be drawing work. On the other hand: the smaller size has many advantages as to distances to be covered. It feels better to select etc.
the advantage of the intuos is the toolbar that comes with it.
I won't use the pen when in a non drawing app, but when I use it, like in PS, I won't use the mouse as its as handy as a mouse once one gets used to it. And I do use a lot of keyboard shortcuts. (even the alt-ones on PC: holding down alt while choosing menus gives you series of letters that can quickly lead you wherever you want.)
so my conclusion is: get a graphire2. and some spare pen-points.
yet: I do have a Logitech wireless optical mouse. And for apps like C4D, I prefer the mouse.