I enjoy playing Slardar because I feel he is a good regulator in team fights or during laning because he has high armor, good stuns, respectable damage output, high HP and his ability to turn tanky heroes into prepubescent LoL players. He is a great pick if the other team has a Riki or Bounty Hunter because his Ult Amplify Damage lowers their already low armor and shows where they are at if they go invisible.
The only starting item that some of you will have a problem with is the quelling blade. It makes last hitting with Slardar a breeze because he already has an excellent attack animation and if you are laning against two ranged heros it just makes your life that much easier but if you feel that you can handle your lane without one buy all means pick up another gauntlet of strength and rush an Urn.
Will flesh items and skills out later.