Intuos owner here:
I chose the intuos over the graphire because of the extra levels of sensitivity, also, intuos has the ability to read pen tilt, and on some pens even rotation, which can be helpful for some calligraphy-type effects.
I'm not sure if the graphire pen comes with extra nibs, but the intuos comes with a couple spares, and a couple specialty nibs: One that has extra travel, so it "feels" like a paintbrush, and one of a material that tends to drag on the tablet, which feels a lot like a felt tipped pen.
Having used the older intuos, there's really not too much different, aside from cosmetics. The only caution I would say on the Intuos 2 is to make sure the drivers are XP compatible. I'm also not sure on the compatibility with newer pens (such as the airbrush tool..) One somewhat nice thing is on mine there's a palette of buttons to the left of the drawing surface that emulate the ctrl, alt, shift and space keys, as well as a small pad that acts as a mouse wheel (great for zooming in and out w/o having to go back to the mouse)
Also, get as big a drawing surface as you can afford (and your desk can hold) you'll thank yourself later.
HTH.