vacantlook
Super Moderator
If my memory is serving, I don't think there's anything in these two seasons that you absolutely must see in one prior to seeing something in the other, with the exception that you'll want to watch the finale of Buffy5 before the finale of Angel2. There's less crossover and more of a bit of synchronicity with a couple of episodes throughout the two series. Like for example, there's a character that shows up on Angel, that is also later in Buffy's season too, but I don't think the two appearances are connected on a plot basis.