Stellar is the best at the moment, it is traded in high volumes and hasn't hit any big exchanges yet.
For the future I'm thinking about XMR (Monero).
OP do not listen to people like this one. Stellar is definitely one of the worst, although the 2nd part is correct. It is being traded/dumped onto smaller exchanges that currently accept it.
Monero is actually pretty decent.
If you want to play safe look here
http://coinmarketcap.com/ then sort by trading volume, market cap.
As always, invest only what you can afford to lose.
Like he said, use this to know which coins are popular/known then do your own research and invest accordingly. Do not invest in something like LTC or Ripple just because it has a high market cap among the altcoins (doing so would be a mistake).
XMR, DRK
Investing in this should not burn you/will make you profit, but do not follow my words. Just take them as a tip and do your own investing later on.