Minus the obvious BTC for the looong term win, I'm going long on:
(1) Sia
(2) Dent
Like you have said, BTC is the number one and anyone who is looking forward to a long term profit should go for it. BTC is the number one on my list, and apart from that , I usually go for those altcoins in the top twenty or so, sometimes, top hundred.
Ethereum is just like bitcoin, not much like it, but it is good and is a second option after Bitcoin. Ripple follows and if Im going to talk about any other coins, its going to be from the top hundred (or twenty) like I have said .