I guess $400. This is like guessing how many gumballs in the jar to win. But I'm with those who predict subsidy with cell based internet. I still don't believe tablets will fly - there is just no point in a giant ipod - you can't put it in your pocket and you can't actually get any work done on it, which to me is the trade off for lugging around laptops and even netbooks. I travel light, even three pounds better have a keyboard and screen that holds its fool self up. I bet most netbooks for that matter become paper weights. Too many people bought them because they were $300. It's like the first time a 1GB SD card came down to "only" $50. I had to have one and it seemed so cheap for so much memory. Ha! Fool that I was. I remember my first 1GHz cpu - I just couldn't believe it and I wanted to be part of progress. (AMD Athlon) So I'm sure many will buy an Apple tablet purely for the Sci-Fi coolness of the idea. But reality will set in.
Now if they could make the screen fold or roll up into an iphone sized package, OK then, serious buy in. Seriously folks, have you ever used a small slate style "tablet pc". It's a pain in the arse for almost everything except web browsing. (I admit slates are kind of fun for web). Maybe looking at photos, but the screens are always too small.
Now if this apple tablet had a hideaway keyboard ala Droid, and a picoprojector with decent lumens, that would be coooool and useful.
Prove me wrong Apple gods!