Alternative tablets to to iPad do exist.... they just aren't very good.
If you want a super light weight tablet with good battery life and apps/games/video/music with 10 hrs battery and high quality capacitive touch LCD, there's nothing else at the moment.
That being said.. show me a place where I can buy the iPad now? It's not released yet and there will be a bunch of competitors improving their products as we speak, to include blutooth and improve their form factor/battery life.
Most competitor 'tablets' are thick chunky slabs which tried to get a laptop into a tablet form factor or are simply mini laptops with a touch screen. Aesthetically, Apple makes good hardware, there is nothing with the form factor of an iPad on the horizon (super slim, 10hrs battery etc etc).