Ok, to start with, those info werent taken by any site like Wowwiki or Allakhazam. I found the following myself, thats why they arent much, but still they made my day :P
1. In Auchindoun, there is a vendor, for poisons, etc. He is named as Slim, Shady Dealer. Obviously its reffering to one of Eminem's song named Slim Shady.
2. Once u enter Nagrand (good ol' days :P) you will see Nesigwary's safari...Woah STV 2.0 :P Anyway, next to him there is a fallen plane, with 2 snakes on it..
Obvious reference to Samuel L. Jackson in Snacks on a plane...
3. There is an npc in Shattrath named Haris Pilton. I lol'ed at it cuz it reminds me of Paris Hilton.
4. Dirty Larry in Shattrath, its like Dirty Harry.
5. R3D0 is a sentinel in toshley's station. As of a fun of Star Wars when i was young, it made me lol :P Cuz C3P0 and R2D2 where 2 robots :P
6. Area 52, this is kinda hillarious, is obviously refering to Area 51, the American military base which serves as a top secret U.S. Air Force testing facility and army weapons
7. In Telaar, Nagrand, there is an npc that gives you a quest, named Lolol :P
----UPDATED------
1. My mate told me that David Wayne is rumored to have crafted Ashbringer.. Well "Wayne" sounds like a reference to Lil Wayne, well known rapper across United States.
2. Caregiver Ophera is innkeeper in Temple of Telhamaat. I found it funny, cuz it looks like Blizzard Devs watch too much of Oprah's tv shows..