A new mount I am working on is the Nether Drake. This awesome flying mount is not easy to obtain. While there is not a lot of hard battling and mob fighting, you do have to gain an exalted reputation with the Netherwing faction. There is a great guide giving you everything you need to get there located at WoWHead.com. Here are a couple of pics I took of my Death Knight riding one in Shadowmoon Valley.
If you try for this mount, good luck, it is expected to be at least a week grind.