Wrath of the Lich King
Create your WoW account
Make your account, verify it properly, then move straight into the client and setup flow. No blank dead-end message, no guessing whether it actually worked.
Version
WoTLK 3.3.5a
Status
Playable
Account Flow
Create + Verify
Next Step
Download + Realmlist
Create WoW Account
Account creation
Username format: 3-16 characters, letters / numbers / underscore only. Password: 6-20 characters.