I can only comment as an ipod Touch user rather than as a phone user but I have been vastly impressed by the additions to the ipod as a result of software 2.0.
I have found the exchange mail support to be a real step forward which eliminates the need to sync my calendar and contacts through iTunes, improving integration significantly.
However something that would therefore have been a real benefit would be some integration with to do/tasks. So far I have not one of the numerous to do add on apps that I get on with, so I have resorted to scheduling appointments with reminders in order to get some sort of integration across my work pc, iPod & home pc. It’s working kind of but it’s not great.
So any suggestions are welcome.