ETH is quite good for quick buy/sale, and Monero is very good from privacy view, so these two altcoins will be Top 2017. Plus Monero price can go up, because more and more people use it. Currently in all crypto market most popular coins are BTC, ETH, Ripple, Litecoin and Monero, see here crypto market
https://coinmarketcap.com/.
I don't really get thepoint you are driving at, buying Monero because of privacy alone doesn't make any investment sense since there are alot of coins offering this service like Zcash, Shadow, Navcoin, Dash etc there must be more that differentiate it further and a solid fundamentals that can drive the price. COncerning the top coins presently, the likes of Dogecoin and NXT were top on the coin marketcap this time last year, where are they now.