Red Cross does a pretty good job. At this point the needy iHubbers are somewhat mythical, we're not even sure they need help. Plus, iHubbers in general are probably wealthier than some of the people who need help right now, IMO.
On a similar topic, here's a group that is matching all donations with an additional 50%, that could help "defray" the overhead portion of an individual contribution so you'd know more of your whole donation is being utilized
The Salvation Army is a member agency of local affiliates of the United Way of America where such affiliation has proven to be beneficial to The Salvation Army. The organization’s stewardship of its funding is noted throughout philanthropy; 83 cents of every dollar collected by the Army goes directly to client service – among the highest percentages of any non-profit in the world.