If you're xp-ing in groups I would recommend the Clockworks in Deathfist Forge (NW i think) for around level 30 groups. Fast respawns and great drops as far as rares go.
Mid 30s - siloths or (those other things next to siloths that also have a HnG)
Around 40 the best camps are either the next set of clocks (Eternal Desert) or Ice Giant Refugees are nice camps.
Picks are alright if you're able to solo them, but finding a camp can be difficult
when you can, purchase the taunt upgrades for pallies. Then around level 25 is when you should start dumping some points into cha without sacrificing too many away from str/sta.