I saw the video of the iphone OS 4 demonstration and was really impressed. I really felt they did a good job with the multi-tasking. There was one fatal flaw (a bit dramatic), the fact that you have to double tap to get to the multi-tasking. I know this sounds petti, but multi tasking should be quick, so I feel it should be one click to get to the multi task screen and then the double click to go to the Home screen. IMO it just makes ten times more sense and will be so much more efficient. Once again, i know this sounds petti, but I think it would make a big difference.