My father had a very rare blood type, AB-. He gave blood every time he was asked. Here's his blood-donor card:
He gave over 50 pints in his lifetime, and was awarded a special gold lapel badge to wear; this, he did quite often. I'd have liked for it to have been in his lapel when he was buried, but we found it too late. Although he deposited a lot of blood into the blood bank, he only ever made one withdrawal, and that was in the last week of his life. He'd still have been well over 50 pints in credit, though — he reached the 50-pint mark in 1980 and continued donating for another 30+ years.
My brother was also a dependable blood donor. He'd donate blood twice a year — I think he managed 49 pints before he died of a heart attack at 47.
My father's belief that donating blood was a civic duty came from his mother. She was a regular blood donor until the needle broke in her arm once and it put her off doing it again.
Unfortunately, I've never given blood. I went to do so once at the university when I was 18, but they told me I wasn't suitable. I don't know what the problem was, but it doesn't seem to have been anything fatal. Whatever, that put an end to my blood-donating ambitions. It's probably just as well, given how hard it is to get the stuff out of me when a doctor wants to run a test.