Hey,
If you're a student, you can get Painter for $80 from an academic software reseller, sometimes they will throw in a graphics tablet for a reduced price as well.
With Wacom tablets, there are two different kinds which you will want to look at: the Graphire and the Intuos. In a nutshell, here are the differences:
Graphire has 512 levels of pressure sensitivity.
Intuos has 1024 levels of pressure sensitivity and supports 'pen tilt'.
Pressure sensitivity is what will make your lines darker/thicker or lighter/thinner, depending on how you set up the brush.
Pen Tilt is a neat feature which will make your strokes do different things depending on how you hold/tilt your pen...sort of like a calligraphy brush.
I like the 'feeling' of the Intous pad, it is a little bit softer and feels more like real paper than the hard plastic of the Graphire pad, plus it has little function buttons on the top which allow you to assign shortcuts to them.
And what's great about these things is that they work with Photoshop and Illustrator as well, it is SO fast using one of these to do detailed masking and painting work rather than using a mouse, and you get better results because we've spent our whole lives using pens and pencils on paper...
Good luck,
Nick