And in answer to Nightnight's other question, what do those of us arguing against the effectiveness of homeopathy hope to achieve - I think that's a really important & interesting question. 
I can only speak for myself, but firstly, I'm arguing against the efficacy of homeopathy (rather than for it) because that is what the evidence seems to me to be saying. I don't have a problem with complementary and alternative medicines per se in the least - I am interested in which ones do, and which ones don't, seem to work. The current thinking is that some forms of herbalism are very effective and there is increasing evidence for acupuncture working for certain kinds of pain relief, for example.
I agree with you absolutely, Nightynight, about homeopathy being a very effective placebo. There is interesting and important research being done at the moment into placebos - how and why they work, what makes some better, etc. Now, surely it is more interesting and useful to actually investigate these issues rather than just saying 'Let's not investigate homeopathy at all for fear of offending believers?'
Finally you are asking what homeopathic arnica users have done to offend us! Nothing at all and I'm sorry if I or anyone else has given that impression.
I have no problem with people on here, or anywhere else saying, 'I believe it works for me' - in fact I think it's fascinating to hear what it works for etc (eg the people who got through labour on just homeopathy - wow!). What I do have a problem with is the large proportion of those who peddle (and are making money from, CAM, and this includes journalists eg in Sunday supplements who are under pressure from advertisers in the CAM industry) talking bollocks, either because they can't be bothered to do their homework (you would not believe the number of times when herbal arnica is conflated with homeopathic, for instance) or because they are trying to make money by exploiting people at vulnerable times.
[takes deep breath]
Should probably parp myself now! 