The reason Im asking is because I gave away my BC disk, and haven't bought WotLK as I quit before it was released. My real question would be, if I want to start again, do I have do get them both back to still feel the authentic WoW experience?
I could just borrow it off a friend, but still..
Plus, I always liked Dranei and Blood Elves, but can't be them if I don't have atleast BC.
The world changes for you no matter what, whether you have just vanilla WoW or every expansion all the way up to and including Cataclysm.
Consider the 'world change' part of Cataclysm just an event associated with the expansion pack that happens for everyone, and the level 80-85 content the
actual expansion pack you're paying for, if that makes more sense for you.
So, after the release, it's vanilla WoW til you're 60, BC til you're 70, WotLK til you're 80, and now Cata til you're 85, except it'll all be in a completely redesigned world.