I'm using 9x12 Intuos 3 tablet, but also effectively used 4x6 tablet for long time before this.
Key apps for me are Photoshop but Also Illustrator. The pen tool there is pressure aware, so you can make some really natural and fluid, but still vector objects. Both the Intuos and 4x6 graphire come with nice mouse with scroll wheel. Driver lets you customize for specific applications, so if you are setting up a new system, you can get the graphire at $100 for about price of nice mouse. This mouse like the pen is cordless and never needs batteries.
One day a Ciintiq would be great, but are a bit pricy for now. Maybe the macebook tablet, will have pressure sensitive display when it comes out?
