If it is long term ethereum or litecoin you can choose any one of them and make your investment long term.Don' try to invest on any shit coins which is giving more profits in trend because it will give only profits for a while and then will lose its value.
If you want to invest on different coins then you can pick NEM as an option because it is promisable coin and it is gonna bump in 2018.Some experts says NEM will hit $10 by end of 2018.I don't know it can be possible but in long term surely it will good profits.