Still holding my UNO of course. The altcoins that interest me most right now are platform based actually. I can see them having a strong future with mass adoption of blockchain tech applies. As we get blockchain-based social media, e-commerce and the likes built with DAPPs or otherwise.

Just looking into SCL, which is still in ICO, it's the Social coin for Nexus platform I just read about on this post by @sanees today. Seems to be designed to cater to the Facebook crowd.

Library (LBC) also looks like a good concept in the early stages, but development and UI seem a little slow. That is a Proof of Storage model for sharing media.

Another platform is NXT, while a lot like ETH, the proof of stake requires a significant amount of NXT to forge a block; upwards of 1,000. It is a Java-based wallet.

I am still holding a little Lisk (LSK) and looking forward to EOS, being a @dan project.

Trouble with most altcoins is that they are currencies, which will most likely never compete with bitcoin. Introduce a platform that is scalable while distributing wealth on an equal (or fair play) basis that third-world users can profit from and you have something.

What do you think? I'm sure there are plenty more out there like NEO that I haven't looked into yet, hard to keep track. :)