Shaman is one of the best classes for farming, constant damage, constant sustain, it's good in pvp as it makes it so opponents cannot crit, and it also has a nuke but I prefer evolved shaman for pvp as it has a stun and I use normal shaman for everyday farming.
Also master ranger is a must-have if you tend to bot alot at map locations that are public, there are too many damn trolls that enjoy messing with botters, I can understand people being mad at runescape bots as it effects in-game economy, but in this game it effects virtually nothing. Reason why it's a must-have for botters is because it can attack from any range, so no more getting moved out of the monster area, I could count dozens of times of me farming elemental and some troll decided to click me out and I spent 30 minutes hitting a phoenix that gave me nothing.