For years I have been using my little wacom Graphire 4" x 6" 3 tablet, and I love it. It's reliable, and portable. I like the fact that I can slip it into my laptop case and take it anywhere. However I really need a tablet that has pressure-sensitivity enabled, and the little Graphire is just too old.
Until I am able to get a better tablet, I may have found a temporary solution: Inklet.
Inklet is a piece of software that allows you to turn the trackpad on your any Mac built after 2009 running at least OSX 10.6 Snow Leopard into a tiny pressure-sensitive tablet. It can be used in conjunction with Photoshop and many other graphics programs. You have the option to use your finger, or a stylus.