( I have just written a post, but it has vanished from the screen

, so apologies if it appears twice......I will try again.)
I have read through the poll, but find I cannot answer it.
I believe now, weighing up all the evidence, that XMRV is a major player, and very likely causative for a substantial subset - if not the majority - of those who fulfil the CCC. Here in the UK, however, you only require the symptom of prolonged fatigue to receive a dignosis of 'CFS' and I don't believe that XMRV will be the answer for that particular group of patients. However, in my experience, the majority of the people who I know who are being currently tested in the current WPI study do fulfil the CCC, so it is possible that they will prove positive. If this should prove to be so, I still don't think that we can then assume that XMRV is the cause of the condition being labelled CFS/ME in the UK because a number do not have the symptoms of ME as defined by Ramsey or by CCC.
For others, who fulfil the CCC, I think it likely that they will have what Dr Hyde refers to as 'Secondary ME' following poisoning by organochlorines and organosphosphates ( I think that the work of the Glasgow team back in the '90s confirmed that) and that others will have a chronic enterovirus infection as hypothesised by Ramsey, Dowsett, Richardson, and now, Dr Chia. (It is, of course, possible that XMRV is triggered by toxic exposure and that the chronic enteroviral infection is a result of a underlying XMRV infection, or even another undiscovered retrovirus. ) At the moment though, if you ask whether I think that XMRV is a major player in CCC ME, and probably causative, the answer is 'yes', I do.