I would start 5 chars on magtheridon, but only play them rested.

Edit: Stop! I've voted Magtheridon, but look at this:
Level 70:
Total Alliance: 2,207 - 29%
Total Horde: 5,485 - 71%
http://www.warcraftrealms.com/census...ervertypeid=-1

dont know about bg waitingtime, maybe a other server would be better...