I have used a Wacon ArtPad 4x5 for some years now. Just as Rawnrr it's the size i would recommend as you don't have to move the arm. Also important is that it don't take much place on the desk witch is important as you should absolutely expect to keep your mouse as well. I would not recommend using the pen for everything. Actually I only use the pen in 2D paint programs in witch the pen is excelent. In 3D applications at best the pen is as god as the mouse and in wors cases it will freek out the application. Niether is handling Windows(or any os) with the pen a god idea. Mainly because of two reasons. One is that the pen pressure witch will work as the left mouse button no longer is digital and the point where it starts to act is not distinct so you will find yourself selecting stuff by misstake and you will drag folders into other folders by misstake. Also double clicking is a lot harder as in order for a operation to be recognized as a double click there has to be two clicks in the same spot. It's not very easy to double click with the pen whithout moving it and it's the same for the functions placed on the button at the pen. Hard to use without moving the pen a little. So.. For 2D painting where the ability to draw flowing lines is needed it's excelent. For 3D (where precision is important) it's better to use the mouse as with that you can reach precision even with your arm relaxed. If you want to do the same with the pen you will have to strain your arm and hand. For Windows handling the mouse is better as less misstakes will be made because when using the mouse you knows when you click and there is no risk the pointer moves when clicking. When I work I use the pen when painting and when doing something else i grab the mouse while still holding the pen. No problems at all working that way. Just my 5 cent