I started with Vanilla. Just a few weeks later BC came out so I bought it so I could do more with the guildies. Have to say I loved both of those the best. But WOTLK is awesome! After that everything changed and although I kept playing I did lose interest. After WOTLK the only expansion I enjoyed was Pandaria. Loved the Chinese environment, the dragon mounts, landscape. To me the perfect repack would be one of WOTLK with Padaria ported into it. Leave the others out of it.