I recommend the Wacom tablet. I use it myself. Although i've had mine for over 7 years, I must say I am very happy with mine [mine is about 4x4 i think?]. If you are a hardcore graphic design artist, I recommend that you buy a big size tablet because it gives you more space to add detail and whatnot. Yes, they are pricey- smallest ones run about over $200+. But I am pretty sure you can find good prices on them on ebay or amazon.

If you're a beginner, I would buy the 6×8 or the 4×6 because it's a pretty decent size. You can try buying on in best buy or some other electronic store in your area.

Now, if you are left handed, [because I am], it can be a bit of an issue to get used to the large size tablets because the buttons that are on the side can be in your way. But if you're not a lefty, then you're fine.

Hope that helped!