Shaco is the best as a jungler (though supposedly there is a bug to that right now).
He can play ap or ad, but ap is much harder and without lichbane much weaker overall though JITB nests are great at trolling the opponent champs with ap shaco.
Ad should always jungle with cloth armor+ full hp (5), rush madreds, get shoes, upgrade to wriggles, then varying builds.
The point to both is to build to increase damage and utility. For ap shaco always grap cooldown reduction to the max 40%, for ad shaco always get wriggles for lifesteal and a strong damage item that also boosts hp. Trinity is a good lategame item on shaco, infinity as well but I'd build it AFTER survivability. I've grown attached to grabbing things like frozen mallet to increase his health and gank strength. Without hp items shacos health doesn't break 2000 (or does just slightly I forget) and he'll die to a still breeze mid to late game)