I had the N91 firmware blues. I was having the theme reset problem and various other weird problems (including a beta version of ShoZu crashing randomly) reported by others as a problem with the V1.00.028.13 29.03.06 RM-43 version of the N91 firmware that I have (apparently V1.10.030 05-05-06 RM-43 and newer versions fix these problems as reported at mobile 9) until I reformatted the hard disk.
Fingers crossed, things are working now (for me a phone isn't working until ShoZu works :-) ! ). It looks like my problems were due to one or more of the following
which were the only apps I had installed (and yes I am well aware as an ex developer of the perils of running beta software which is why I am not flaming or blaming anybody :-) ! ).
UPDATE: As always, Darla Mack has a more thorough Nokia Wireless Keyboard review.
Back in October 2005, on my way home from BarCamp Amsterdam, in a jet lagged stupor, I picked up a Nokia Bluetooth Keyboard aka the SU-8W. Maybe it was me, maybe it was the earlier version of the software, maybe it was my old grey market 7610, its old firmware, and its limited RAM but it did not work very well. The keyboard would disconnect and power down after a certain period of time and it did not reconnect when you rebooted the keyboard.
I am glad to say that it works much better with my N70. For work and fun (!) I monitor several servers. Now wherever I go, I carry my N70 and the SU-8W and monitor and tinker with the servers remotely using PuTTY (which allows me to login and work on my servers securely over SSH). It works really well (the keyboard automatically reconnects when you turn it on, unlike my 7610). Highly recommended.
Nokia, please introduce a series 60 phone with a 3 megapixel camera, optical zoom, macro mode and 640x480 video and a keyboard. I will pay for one of these bricks :-) (basically an N93 with a keyboard!) with my own money!