Over the course of many years, I have contributed some substantial money to various charities -- things I believe in enough to support. When I say "substantial" amount of money, it is, of course, all relative. My contributions would be a drop in the bucket from some wealthy celebrity, but again, it's all relative and it's the "thought that counts".
I have never, ever, ever given a charitable contribution for the tax write off (and trust me, the write off would be very small anyway -- because as mentioned above, what I account for as being a "substantial" contribution, adds up and means very little when it comes to getting tax credits from the IRS).
I used to contribute to the likes of Greenpeace, PETA, etc. I stopped several years ago, for my own personal reasons and don't feel a bit guilty about it. Also several years ago, I learned that one of the places which I routinely contributed -- Disabled American Veterans (or whatever the official name is) very, very rarely used the donations properly (read Zen's comments above) -- not only did I immediately stop sending any more money to them, I requested that they stop sending me any free items or requests for donations -- I was disappointed and angry to learn this information. Hence, I took the time to review other organizations to which I had always supported to be sure that my money was not being wasted.
Overall, I tend to support the "little guy", the one who doesn't get any funding from the govt' but who works really, really hard at their cause and has people who work with them for the love of the cause. Again, when I'm making a financial contribution, I give what I can, when I can. At the end of the year, when I do my taxes, I am sometimes quite surprised at how much I had contributed throughout the year -- but the tax deduction is just a plus for me at the end of the year, it's never thought of while I'm making a contribution.
I know the places I like to contribute to and I'm happy to do it. I don't usually contribute to the American Cancer Society (although they do great work) but will pass them over and give towards HIV Research instead. Why? Well, because ACR receives more funding from various sources, while HIV Research does not. Again, why? Well, because society tends to frown upon those with HIV -- blaming the person's lifestyle, for the disease; cancer is just an ugly disease that any one of us can/do get (even though some cancers are directly related to our lifestyles). But overall, I just tend to go for the underdog (in just about everything in life) and very rarely have I been disappointed with that approach.
Speaking of "underdogs" -- my next contribution (tax deductible or not) will be to a place called "Finding Shelter" -- it's a very small animal shelter in Norristown, PA, started by some very sweet, giving people. I'm planning on attending their annual event, "Sproutfest" (it's in honor of their one rescue, Sprout, who was meant to die awhile ago and is still very much alive and kicking . . . because of these folks). Anyway, Sproutfest is an animal adoption event, being held in King of Prussia, PA (for anyone here who might be interested and nearby), on Sunday, October 23, 2011. I'm going to check it out . . . putting my nose to the ground and sniffing out my new pup while I'm there! Can't wait!