Another K800i owner here. My contract expired months ago but just haven't seen anything to tempt me into upgrading yet as the C905 still seems to be having reliability issues which may or may not have been resolved with the C905+. Whilst the only Nokia i could liked with a Xenon flash, N82, was discontinued by o2.
The C901 sounds good and hopefully will prove to be an ideal replacement for my K800 which has started to develop some quirky behaviour in recent months!