This is my usual build for slark. Tend to win with great ease and dominance, as slark is really powerful in pubs and can lane anywhere. I feel these items best maximize his potential as a gank/carry. His best lane will be mid or safelane, but slark can offlane as well if done carefully. You just need to be passiv in unfavorable lanes until you reach level 6. The sooner the better, so he should solo lane as much as possible without crippling farm.