I'm a big fan of Swiftkey X for tablets. The default keyboard is nice because of the two shift keys but having to press one key to get to numbers instead of a long press is hard to get used to. Swiftkey has a split keyboard option or a normal keyboard with the split having letters on either side and numbers in the middle plus it learns as you type and has a lot of customisation in themes, key height and width, long press duration.
.... I realise that sounds like a big ad but I promise you I'm as jobless as they come, just a fan of a good and usable keyboard. I have the phone version as well but I'm really liking the new HTC Sense 3.5 swipe enabled keyboard.