Personally I like Earth.
Fire is good for AoE and those "up in your face". Air is good for support and direct attacks. 20% penetration, blindness, weakness, knockdown, running, lightning damage, all are good. Water, yes good for snares (slow so you can drop a meteor shower on them

), knockdown those who move, armor protection, interupt in a small area. Earth, wards, armor, ignore armor attack, knockdown, blind, slow down a single enemy.
Many like Monks as a 2ndary. Rangers can be okay (wilderness survival can manipulate all damage into fire or cold, so you can set yourself up in your defense). Ritualists are okay (hard rez, spirits, healing, etc.). Warriors for stances.
The main thing you must know is:
1) you have low armor, so either move around, or have good defenses
2) you have one of the worst healings in the game (I would say tied with Mesmer), get a 2nd profession with good healing skills (or at least acceptable)
3) PuGs expect AoE Fire damage from you, if you choose not to, tell people and your reason why.
Elementalists are usually wanted, sometimes required (unless the group is amazing in PvE).
Enjoy!