Always hold some level of Bitcoins but not all. I would say some notable coins that you should consider are:
1. Ethereum
2. Stellar Lumens
3. Waves
I think those have pretty good potentials to grow in the future. Ethereum is obviously and undeniably the forerunner in its class and it is pretty much one of the most developed with a robust community behind it. Stellar is a very interesting coin which could be the currency we need to enable us to use for micro-payments in real world transactions. Lastly, Waves is something similar to Ethereum, but has features that stands out. It also has very active community and development and could rival Ethereum in the future which could lead the price to increase by a lot in the future.
Stellar is an open source platform specifically designed to enable fast, cheap transactions - big or small - even those under $1. The only problem with Lumens is that they are principally designed to make the network function, and the number created is astronomical. In addition, Stellar has an inflation feature which adds Lumens to circulation.
From an investor's standpoint, deflation would foster token appreciation - the opposite of what Stellar does with Lumens.
The tokens of companies that
build on the Stellar network will enable fast, cheap transactions. The trick is to find companies which will not only be able to provide those services, but also will be dedicated to their investors.
There is at least one company that has designed its Stellar token to gain value over time, making it perfect for long term investing.
MONETRAN.COM