Oh wow, where to begin. I could write pages and pages on this topic, but will try to keep myself under control. Personally, I would invest in Ether (ETH) and Ethereum based tokens. Augur Reputation tokens (REP) just launched recently on the Ethereum blockchain (I bought into the ICO a year ago) and have dropped a bit in value, making it a good opportunity to cost-average your way into a position. The Augur platform itself will launch within a few months. It's a decentralized prediction market which has the potential to be a killer application for Ethereum. Expect a large run up in REP price as the official launch approaches.

Synereo AMP also looks like a good long-term opportunity. See my previous blog post about it for more detailed advice about that.

When it comes to evaluating altcoins, I stay away from everything that is simply "a better Bitcoin" (in other words the vast majority of them). I look for innovative new blockchain 2.0 projects that offer something new and unique, above and beyond the standard store-of-value / currency aspect that Bitcoin is designed for. This is why I like Ethereum, which is a smart contracts platform (think Bitcoin but with a complete programming language built into the blockchain). Tokens on top of Ethereum, such as REP, DGD, and SNGLS all offer additional ways to generate revenue, like a dividend, which gives them built-in intrinsic value.

Other factors to consider: what are the credentials of the dev team behind the project, does the project have a well-defined development plan with clear milestones, how long has the project already been in development, how much do the devs interact with the community, and what is the potential competition (i.e. will this project corner a niche market or will there be a lot of competition limiting the potential market share).