Right now the two health related charities that are in full swing (Annual drives) are for Leukemia and Breast Cancer.
The Leukemia foundation that I prefer because of low administrative overhead is
http://www.lightthenight.org/hm_ltn
Another approach would be to donate to the rarer afflictions that typically don't garner alot of attention.
Anything related to kids or animals is a nice investment in time and/or money.