I think it depends on what they are. Sometimes they can be hilarious like the 360/Wii reference in Ratchet and Clank Future: Tools of Destruction. Other times, it's like "Meh...." like the guy buried in the sand with his head sticking out in Far Cry 3.
I feel like that Far Cry 3 one was more of a "wink-wink" kinda egg, for those who were familiar with the story behind it. Far Cry also had great refrences to Bioshock, Assassin's Creed, Portal, as well as that awesome Modern Warfare one that made me lol.