Android for mobile devices really is catching on. As much as I love the platform, there are two major flaws that stick out like a sore thumb:

You can't encrypt your entire phones contents- although there are apps to encrypt parts of your phone like sms messages and some of the memory card contents (like , if your phone is lost, stolen, or otherwise), there is the possibility of the retrieval of data from the phone.

You can't lock down the phone hardware itself - again if the phone is lost, stolen or otherwise, it can be wiped completely and the hardware reused without too much trouble or fancy hardware tools.

Curently in the linux world there are several options for encrypting entire filesystems and the Android platform does not seem to be heading in that direction. For enterprise organizations, this may be an issue where a certian level of security is required for employee mobile devices.

There are rumors that the Android 3.0 platform will have some form of data encryption for files stored on your device which is a start, but in my opinion just not acceptable enough.