I think you and OftenBen might find the book Strangers Drowning by Larissa MacFarquhar interesting. It's precisely that: a plethora of perspectives on how to be charitable, from different kinds of people in different parts in the world, interspersed with the ideas and history of altruism. Singer gets mentioned often (not always charitably). Personally, I think charities are most useful when they use their expertise to enable people or places to make significant progress. That can be progress in technology, government or research. There are more than enough charities focused on 'awareness' (read: viral marketing) that could die in a fire and the world wouldn't be worse off. *cough*susangkomencough* I also think that there's this bigger category of 'Doing Good in the World' that is much more important to me. It might be naive to consider it reachable, but I want to leave the world better than I found it. To quote Augustus: "I found Rome a city of brick, and left it a city of marble"The sheer spectrum of perspectives I've come across has been really impressive.
Ut iure sit gloriatus marmoream se relinquere, quam latericiam accepisset*.