I've been using my Wacom graphire for over 10 years now, too -- actually may be closer to 15 years. They last a long time. 

My thoughts:

If you've never used one, don't get a hypersensitive one. Some of the added features may actually be more annoying than useful. As everyone suggests, get a Bamboo.

Size: if you're an artist who likes to make sweeping motions with the pen, the way you would on a reasonably large sketch pad, then a big pad is what you want. If, on the other hand, you tend to use very tiny strokes in a super detailed way, then a smaller pad is what you need because you'll find on a big pad that you need to make bigger motions to move the same distance over the same pixels. This is why I prefer a smaller pad. (And also why starting out with a less expensive version is the best option.) Some artists will do best if they have more than one size and switch between them. :)

You'll wonder why on earth you didn't get one earlier. :) 

But I'm with Tony. In many instances, the mouse is still a very good tool. (Except for 2D drawing, where I find a tablet to be absolutely essential.)

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PoserPro 2014, PS CS5.5 Ext, Nikon D300. Win 8, i7-4770 @ 3.4 GHz, AMD Radeon 8570, 12 GB RAM.