By and large, local animal charities tend to be more efficient. Check your local SPCA on your favorite watchdog site (CharityNavigator is a good one). And never underestimate the good that you can do by contributing time, or even your old towels and blankets.

If you prefer bigger charities that give a lot of feedback, Best Friends (bestfriends.org) is a good one; they do a LOT of media advocacy for adoption rather than buying.

Also, don't confuse the older Humane Society with HSUS - that name was co-opted on purpose, and now we're starting to see why.

Love, Columbine