I think I will never go further than top 50 because it kills the market capitalism and then it gets dangerous to invest into such coin. It will not take much time for such coins to get drained off and then make you loose your profits.
So its better stay above top 50 and then choose. For sure Ether is my motive for now and looking at the current rate of rising it looks to me perfect investment. The second coin is well within top 5 and thats Ripple. A very very good investment and very cheap at this point. Being centralised it stands all the time high in market capitalism. So these are two for now. And if third one then I will suggest Dash becaus somewhow it is keeping itself upwards when other currencies are down.