I got to play with one at an Apple store this morning. I'll join with the other predictions.
this will be the best selling iPad within a year.
The size and feel of it in your hands is fantastic. I am so glad that Apple is moving away from those thin, butter knife edges and to these smooth, full rad corners. It's so much nicer to hold.
The weight and single handed use of the ipad, combined with compatibility of the full iPad app catalog is going to make it very popular, regardless of the price. And, unlike other 7" tablets I've used in store demos, the ipad mini didn't feel cramped when displaying full web pages. I never liked the 7" models since they were so skinny in portrait mode that I thought they were only good for reading single column text and sacrificed too much screen real estate to deliver their light weight. The mini gets much closer to an ideal balance. I'd probably still prefer to use stuff like iPhoto and Numbers on the 10" model but I'd rather read gaf and twitter on the 8".
And, surprisingly, I didn't hate the screen. I loaded up NYTimes.com and a few other text heavy sites and, yes, it was worse than the ipad 3 but it was better than the first two ipads and text was clearly legible to me without having blocky pixels become too obvious. I was using it at the approximate distances I would use it at home. 12 to 24 inches away. I could live with this display. Luckily, though, this display is a temporary thing as ipad minis will surely get the retina screen in an iteration (or two). And then, man, it might be... perfect?