Check out www.monoprice.com for cheap, but extremely functional tablets. I got mine for $70 and it has all the same features and sensitivity of a $400 dollar wacom tablet. If you're not used to drawing on a tablet, I always recommend it since it's not a huge investment, but it'll see you through with all the necessities. Plus, it's a simple installation, and you can generally just plug it in and go, so that's awesome. ^_^ As far as I've seen, almost all the people that buy it (including myself) are really happy with the product. Everyone always recommends the expensive wacom tablets, so this is just me suggesting something more affordable and, IMO, just as good. ^_^ Hope that helped!
The tablet for beginners is call the mouse. It is also used by professionals for a long time. I always use a mouse.
The tablet don't replace the pencil. One of the other things people talk about is scanning drawings, because that is the better way to get line art when they can't draw them with a mouse or a tablet.
Just because asked what is the best tablet, that is what you are going to get.
After you get a tablet, it will be a good idea to put the mouse away and never use it again, because there will be times when you feel you the mouse is better. Using the mouse just makes it take longer to learn how to use the tablet.