I hate using a lot of active skills, so I made a Wizard whose theme is Cold Wizard.
I have only 2 active skills - Ray of Frost on left mouse, and Blizzard on Right Mouse. I chose the two options that reduce their Arcane Power Cost to 11 and 13 respectively.
Then my 1-4 buttons are the Arcane Orbs, Cold Armor, Cold Familiar, and I think the Arcane Magical Weapon skill - essentially 4 passives that I have to keep up every once in a while - the Arcane Orbs most of the time.
My passives are of course Cold Blooded, Astral Presence (for all the arcane power I use), Unwavering Will (because I am standing still a lot shooting my beam and keeping people away) and lastly Audacity because once they get to me they usually freeze and I can nuke them up close.
http://us.battle.net/d3/en/calculator/wizard#ZlcfSj!XWSi!abZaZZ
It is an extremely simple build to play and seems effective, though I have had some troubles with survivability in certain circumstances. I might trade our Audacity for one of the shield-creating passives.
As for gear I focus on cold skill dmg increases, and Ray of Frost or Blizzard dmg increases.