My mom's side of the family are all from the UK, and there's quite a bit of information available there. There were censuses held in the UK every 10 years from 1841, so that's been quite useful in putting together information from my great-grandparents' generation and back - all of my grandparents are dead, so my mom is only resource I have in that regard.
The census records can be viewed through ancestry.com, although it's a little weird as sometimes they'll show the whole record and other times they say that you have to pay to view it, and it seems a little random as to what they let you see - one member of a household might be visible but another not. So the information is all there, but it ca involve putting together various separate pieces.
My dad's family is all from South Africa, which is where it gets trickier. Not so much for my grandmother, as there's a cousin who's done a lot of work there, but I don't know of anyone who's done something similar for grandfather. He wasn't originally from Cape Town, so that does make looking for physical records more complicated, although the town he was born in is only about an hour away (if that), so visiting there isn't a major endeavour if I ever feel that way inclined.
But for now, researching my mom's family is keeping me busy enough. The past few nights it's been a case of "let me just look up one thing before I go to bed", and two hours later I'm still at it.