Dad:
Came from a very WASP-y country club Republican family; volunteered for Goldwater back in 1964 in his youth. So you'd expect straight Republican, right? Well, I'm assuming he did vote straight Republican for many years. But not recently: Clinton's moderation, and his disgust with the Religious Right and neocon interventionism, have made him a swing voter that leans Democratic on the federal level. Since 1992 (the first election I was old enough to notice; was 7 then):
1992- H.W. Bush (R)
1996- Bill Clinton (D)
2000- I'm honestly not sure; he disliked both candidates
2004- John Kerry (D)
2008- Barack Obama (D)
Mom:
Her parents were technically born here but spent their childhood in Poland, the sort of working-class Catholic whites that probably voted in huge numbers for Kennedy in 1960 and Reagan in 1980. She was politically apathetic for most of her life, probably a mild liberal on social issues and mild conservative on economics. Then three things happened: Lewinsky, 9-11, and Fox News, and she took a hard right turn. These days I try to avoid talking politics with her.
I think 1992 might have been the first time she voted in a long time; pretty sure it's been straight R since then.
Grandparents:
I'm pretty sure they were all heavily Republican. Most of my family has historically been pretty conservative, but a couple of my cousins (and probably one of my uncles) are definitely D-leaning.