Nexus 7 if you're a competent adult or the Hudl if you're a kid.
No doubting that iPad is best, but it is only marginally better than the Nexus and therefore not worth the huge additional money - plus you then become one of Apples bitches who will rape your wallett forever more.
The Hudl is the best of the budget tablets and if you use Tesco Clubcard vouchers you get double discount. I have purchased this for my seven year olds crimbo pressie. She wanted a camera or a DS or an MP3 player - this is all rolled into one. Bargain.