The best iPad screen protector for you will depend on what you want it for. If you're going to carry your iPad in a case or sleeve and simply want a little extra protection against scratches, then you could get away with one of the cheapest iPad screen protectors like the Olixar Screen Protector.
However, if you think you're going to use it a lot without a case or sleeve and want extra confidence – particularly if you have one of the more expensive iPads, then you might want to invest in some more heavy duty protection such as the ZAGG InvisibleShield Glass Screen Protector.
Artists and illustrators, or indeed anyone who is going to use a stylus a lot on an iPad might have other requirements than simply protecting the screen, wanting a surface that will enhance their experience with the stylus. For that we recommend Paperlike, at number 1 in our list of the best iPad screen protectors, because it actually improves the feel of writing and drawing on the tablet.