In our iPhone OS 4.0 wish list story from last summer, we pointed out that the iPhone could use a . As it stands, for example, you can't view any mail attachments outside the iPhone's e-mail app. The same holds true for the iPad.
If you're like me and have several e-mail accounts, you may find yourself a little frustrated by the lack of a unified inbox. To view e-mails from another account, you have to back out of the inbox you're viewing, then go to the other account's inbox. Hopefully we'll see this in the next revision of the iPhone/iPad OS.