This is a hard one! Probably the travel diaries, because well, we get make videos in beautiful places, and sometimes we get to vlog from Disneyland! (Because I go there far too much.)
Also, I think some of the best vlogs come from unplanned moments. For example, Lia and I ordered dominoes once and instead of ordering potato wedges, I ordered NINE pots of garlic and herb dip by accident. I don't even know how I did it. Anyway we managed to get a whole vlog based around it, but it was a genuinely fun moment, a lot of the footage is just us cracking up, but it's great.