I've been looking at this for a few weeks now to see if I can justify moving up from my old Sony to High Definition. It would seem that there isn't a lot to choose between Canon, Sony, Panasonic, Sanyo and Samsung. I have been reading reviews and possible getting myself confused between 1080i and 1080p etc. But it does seem that you get what you pay for in storage and low light capability. One of my concerns is editing High Def video on my PC as I don't have a Blu-Ray writer and worry that I will not be able to export it in High Def. I also gather that you need loads of HD and a good processor and RAM. Reviews also state that it is worthwhile getting optical image stablisation.
I think that the CX105E is the newer model. I have read the reviews on it and am undecided. Currently I am not sure I can justify the change as it would seem that I would need to spend over £500 to get good results.