I think there is a bug in the email... I have some weird things happening with the iphone 4 and email as well... the two-line preview works intermittently, and also after reading new mail, often times the messages are still displayed as "new" even though on the email website, it says they've been ready. So I think they have a bit of work to do here for the first patch.
Additionally, another bug (or omission... or I'm doing something wrong) is that when viewing the "Artists" in iPod mode, there are no divisions for the different letters that the bands start with. Not a deal breaker by any means, but just kind of annoying and tougher to read than the previous versions. This issue doesn't appear to exist with the "Songs" or "Albums" searches.