You should also take into account, that the leveling process takes significantly longer and if you want to be decent in RvR you will want gear. Gear comes either from Money or from Farming.
If trio and only trio, I suggest berserker, skald and shamy for farming reasons.
if RvR is your trio's choice and you will want to play BD and HU, then I back the suggestion for the Skald as 3rd class for above mentioned reasons.
Enjoy and welcome onboard
"Just dot it..."
A Midgard Shaman and Redcaps' bane
Dotit, Blockit, Shootit, Shoutit, Critit, Impaleit, Buffit, Bombit, Workit, A Shadowblade