I think it would be of immeasurable help to all players if there was a way GW2 could add a line of code to highlight our friends list, or send an auto alert, when a friend on that list is online.
My habits are the same of a lot of players, we log on, check to see who is on from the friends list, proceed to play, get so caught up in the game, we forget to check for our friends until we are ready to log out. This defeats the purpose of a friends list. Not all friends are in the same guild.
Perhaps this is a small convenience we should have in one manner or another.