Hello..[Wotlk] or MOP

I'm new player here...Nice to miss you guy :D... i just wonder...
which one between Wraith of The Lich King or Mist of Pandarias. i should play...Thanks guy

It tottaly depends on you! I personally like Wrath of the Lich King most, i also kinda liked cataclysm but post-cata.. meh, i wouldn't play those, only wotlk and cata

Depends on what you want to play, but upcoming Lordaeron is the ones that will bring the most complete gaming experience so far.

sorry but all servers in warmane are using the same expansions?

No, there are a few servers in each expansion (Between WotLK and MoP)

Only one in MoP though