I'm still trying to decide what to make my first character. Thinking something ranged, either a witch nuker, a duelist or ranger bow user, or maybe a caster templar. I guess I should play around with the skill tree a bit before I decide.
One thing everyone should be aware of:
http://www.pathofexile.com/forum/view-thread/15223
There are a multitude of special merchant "recipes" where selling the correct combination of items to a merchant gives you something special in return, instead of the basic wisdom shards.
Particularly nice early on is the onyx amulet.
Recipe: Amulet + red Gem + blue Gem + green Gem
Reward: "Onyx" Amulet +10-20 to all stats
Also note that you can trade a combined 40% quality worth of armor (or weapons, or other item type) for a quality increasing item, so when you are deciding which junk items to pick up it's often worth taking items of quality even if the item is garbage otherwise.