I give my time rather than money in almost every case. The main time that I actually donate is at Christmas to a favourite charity of mine, and if a friend is fundraising - e.g. running a marathon or has organised an event, then I will likely donate to support their thoughtfulness and their efforts.
Personally, I get a lot out of volunteering and find it a valuable use of my time. I enjoy directly seeing the impact of giving up my time for others, and I find you learn more about the charity by volunteering with them.
I tend to do event volunteering as it combines better with my kids and still find this valuable.