A frequent problem with today's non-iPhone mobile devices is that they carry over paradigms from the desktop that don't really fit the device's form factor. Like a start menu. Or any menu at all for that matter. The problem with a mobile device is twofold: it has a smaller screen than the desktop and navigation on that smaller screen is less exact due to navigation tools operated via a thumb or finger. The iPhone solves this problem by not having menus. For example, I have a picture in front of me of the menu in the BlackBerry mail app. I see Help, Mark Prior Opened, Delete Prior, Compose Email, Compose PIN, Place Call, Compose SMS Text, Compose MMS, Blackberry Messenger, Search, View Folder, View Saved Messages, Options, Reconcile Now, Switch Application, and Close. Sixteen items. If I consolidate a couple of those and remove a few that shouldn't be there at all, I would end up with a list that goes: Compose Email, Switch to Messaging, Search, Options, Get Mail, and Close Menu. Six items. From sixteen. The disadvantage of this is that now a messaging screen is required for the messaging items. Shouldn't be too hard, it can have larger text now that the items aren't in a menu at the side.
Menus are only one of the interface paradigms on the desktop that aren't on the mobile. To list a few off of the top of my head, Menus, Cut and Paste, Drag and Drop (you don't have more than one window open, ever!), multiple windows, large text entry areas, or particularly long forms. Mobile platforms are more in need of designers than desktop platforms, as it is difficult to take advantage of the limited screen space.
On the same note, but completely different, I recently got to see a BlackBerry bold. The solution to not enough space is not to make all of your UI widgets smaller (though nice job on the anti-aliasing).
