I'm a fan of cystic fibrosis charities, since I actually knew a few people with CF. However, there are many that feel that it's best to donate to a particular person/family than the disease's association (i.e. CFF). I do a little of both.
"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." - Carl Sagan