Right now so many good promising Altr coin in a very cheap price specially Eth LTC NEO . These 3 coin is my one of the best coin so if you want to go for longterm Invest I think Eth is the best option.
It is better to get something from the coins with the lower cost, which are now on the bottom. For investment is quite suitable WAVES, you can also look at the exchange ABCC, it has its own coin.