I also thought they were quite strong at the moment. I looked to see what my 2007 335i would go for and it seemed pretty decent. You have found a lot of examples and the fact that you have little intrest in yours proves otherwise though. I suppose I am looking for the higher prices to make myself feel better and you are doing the opposite.
It could be the old 'you will allways find what you want to see for if you look hard enough' plays a small part.
Bottom line is that it is only worth what someone is willing to pay for it and if you have no punters then it is probably not worth what you are asking which is not a good sign. Also worth considering rear wheel bigger engine cars allways haev a bit of a slow winter.
Am I going mental or has it really been 8 years since the second half of 2006?