Rogue

Rogues like most other dps classes are excellent to grind gold with.

The objective here is to minimize downtime due to HP loss and repairs.

This is fairly simple. If there is more then 1 mob just sap 1 and kill the other. In 1 of the resent patches improved sap was given as a base skill so you wont even loose stealth. Then you want to use a stunlock to pretty much kill the mob before it can even hit you. Starting off with Cheapshot then a Kidneyshot at 4 or 5 combo points and sometimes a gouge to get positionals in if your assassin speced.

Choosing Humanoid mobs is usually a good idea because you can Sap them and you can pick pocket them for some extra gold. The Blood Elf's on top of Black temple or at eclipse point or the consortium rep mobs in netherstorm are perfect for rogue gold grinding.