http://buffy.wikia.com/wiki/Viewing_order_suggestion_for_Buffy_and_Angel
http://josswhedon.blogspot.com/2012/04/buffy-and-angel-episode-viewing-order.html?m=1
This is a list of the best episodes from the television programs of Joss Whedon. (And no, Agents of S.H.I.E.L.D. is not on this list.)
The optimal viewing order for episode of Buffy the Vampire Slayer and Angel, to keep the shows in chronological order as they crossover
http://slayalive.com/showthread.php/3924-The-Buffy-Angel-watching-guide
Buffyverse
by Robert Beardsley