Chicobandido.com has done an analysis of the HSUS 2008 tax filing and followed the money.
HSUS spent one-half of one percent on animal care. One-half of one cent of every dollar donated.
Inform yourself before you donate. Support your local rescues and shelters, to you know your money is really going to the animals.
Side note: If you want to support Toronto Humane Society animals and not THS lawyers, the OSPCA has a trust account for THS animal care. Go to any bank and do a direct deposit to the following:
TD Canada Trust account number: 5224209
Transit number: 0307