The thing you need to appreciate about Guild Wars is that your secondary profession reflects how you want to play your character - in other words, the best secondary is determined by what exactly you want to do. In general, monk is a good secondary for any profession, as it provides fast and effective self-healing. Beginning Rangers are also often found with a Warrior or Mesmer secondary. Beginning Eles, on the other hand, most often use Ranger or Mesmer.
As for farming, there are many, many places to farm for many different things. One of my personal favorites is in the Fissure of Woe as a Ranger/Mesmer:
R/Me Solo FoW Farmer