I used to have a standing order for Cancer Research, but they continually badgered me to increase the amount (which I did several times) and in the end I cancelled it.
Although I still put money in collecting boxes, simply because I cannot pass them by, I now support MacMillan Nurses and the hospices - both excellent causes.
Incidentally, my family does suffer from a genetic cancer, so I know how valuable cancer research is. However, having been heavily involved in my professional life with several major charities, I have seen the waste and abuse of funds - and I've also seen the State of the Art Head Offices and the expense accounts paid for from those funds.