No, they aren't. Those won't be even remotely usable on the screen estate the phone has. Evolution is unusable on my 1024x600 Netbook, I cannot even fathom how it would look like on 800x480 (especially the 480 are a problem).

Same goes for thunderbird or *any* three-panel mail client. Look at the claws version which is available for the N8x0 - unusable, even with the stylus.

Devices like the n900 need a cleaner interface which isn't that cluttered. From that perspective modest looks usable, but somehow other things seem to have been forgotten in modest.

mutt and/or pine might be usable, though, as the device has a keyboard