For me it's WOTLK, but I find it really interesting how close the poll is. I see you cleverly asked for our 'favourite' era, rather than the 'best', and I think the reason that the poll is so close is because people relate 'favourite' to 'having the most fun'.
For some people, the most exciting time would have been exploring the world for the first time. Or perhaps exploring it all over again a second time. For others, it may be the first time they entered a serious raid or PvP battle. Or it could even be a period when the people they were playing with were really fun.
My thinking is that the reason the poll is so balanced is because WoW has never been bad. There's always been plenty of opportunities to make the game phenomenal, and when players invested in the game the most, that's when it was most fun for them. And, subsequently, that was their best era.
For some people, the most exciting time would have been exploring the world for the first time. Or perhaps exploring it all over again a second time. For others, it may be the first time they entered a serious raid or PvP battle. Or it could even be a period when the people they were playing with were really fun.
My thinking is that the reason the poll is so balanced is because WoW has never been bad. There's always been plenty of opportunities to make the game phenomenal, and when players invested in the game the most, that's when it was most fun for them. And, subsequently, that was their best era.