If you don't qualify for altcoins or Bitcoin, then Bitcoin would always be that coin that could be best held for years or for long term investment. However, what I am not sure of is your time frame of five to ten years, I say that because that's too long even for Bitcoin; this market has so many changes happening in a day, what more in a month, and more so in a year, therefore, the relevance of one asset is always in question, especially if you are looking at such a long time. Maybe one or two years would be enough, at least make it closer mate.