There are so many which I want to write here. But I will tell you my suggestion:

1. ETH
2. WAVES
3. IOTA
4. RIPPLE
5. NEO

Is it the best time to sell ether? No, it is the best time to hold ether!

I think the price will soon reach 800 $ and more.

The function of the cryptokitties project is stable and secure and shows the very high potential of the ethereum-blockchain.

At the moment XRP has the best digital asset for payments in speed, cost and scalability per transaction.

That will keep the price up.

I think 2018 will be the year of NEO. There are a lot of ICO that will be starting on the NEO platform.
And at the moment the team is on asia tour and right now in japan for meetup. There will be more and more partnerships in future.

NEO price predictions? I think 45$ until this end of year. And then 120$ mid 2018.

I am speculating at a value of 50.000 $. But anything it possible with Bitcoin. 2017 was a turbulent year with lot of surprises.
Next year will be many good news to come. And it is until now not too late to invest if Bitcoin will really increase to 100.000 $ in 2018.

I would suggest to buy step by step like 100-200 IOTA when entering an acceptable price and just monitor IOTA-price all the time or put an order with your preferred price by the bitfinex exchange.

Especially I would say the best altcoin to invest in december would be right now WAVES (Waves-NG & DEX) and SHIFT (Phantom release).

@ coinpuller

Check mal den Altcoin Triggers (Blockchain Defense Technology) und die Roadmap ab. Ist ein sehr interessantes Projekt mit hohem Potential. Bereits ab 1500 TRIG hat du eine Masternode. Der Kurs steht momentan bei etwa 0.85 $. Vor ca. 2 Wochen war der Preis kurzzeitig mal auf 1.50 $ gegangen, als ein meeting mit der NASA Earth stattfand. Der ATH lag mal bei 2.21 $ im September.

There are now well-known musicians like Mariah Carey, Marilyn Manson, Slayer, Sia, Motorhead and more than 40 other top artists which are accepting the privacy-oriented cryptocurrency monero in their onlineshops. By some onlineshops there will be automatically a discount up to 15 % by paying with Monero. The project called Coral Reef for e-commerce.

@Imrhos

I am not sure if you are looking for this coin but just check it out. I have read once about Winding Tree. A Decentralized Travel Distribution. They want to make travel cheaper for consumers and more profitable for suppliers.

I think TRIG is a coin or project with a high potential. Just give the team some time. Triggers cooperate already with the philippine national police.
So the first step is done and many good news will follow for sure. And 1500 TRIG coins are still cheap at the moment for becoming a masternode. I have read that the blocksafe masternodes will earn 25 % monthly.

I think the best crypto to buy now is SHIFT (decentralized web). Very soon SHIFT will release the phantom storage dApp update on testnet, which will make it the first working prototype in this niche ever successfully released. By the way they will also release a new website with a new roadmap and present an extended team. Actually it is only available on Bittrex and Livecoin. But I think there will be soon other big exchanges.

My prediction for a long term hodl cryptos are SONM, TRIG, AMB, Power Ledger, Stellar Lumens, XRP and of course BITCOIN.

Long time ago I have been not more invested in an ICO. But now I have read about the HDAC ICO and I deciced to invest there.
The grandson of Hyundai Group founder is the head and creator of the HDAC blockchain, an IoT contract and payment platform.

Ang isang future project ng mga altcoins is IOTA. Ito ay ang next generation ng blockchain based sa "tangle". Especially ang focus na sa machine payments without any fees. Located ang IOTA project sa Berlin. Ngayon may cooperation na sila with Cisco, Volkswagen, Samsung at Microsoft. May existing din na partnership with BOSCH at Fujitsu. Still cheap pa itong altcoin kasi mataas tlaga ang potential nya para sa industrial applications.

YES, absolutely how many in this forum called IOTA a scam. I think so many times that it could be a new guiness world record.

Now they have seen the cooperations with Cisco, Volkswagen, Samsung and Microsoft. But I strongly believe that this is only the beginning!

If I have 250 ETH I will hold it for another year. I think the price will increase much more in 2018. Only if there will be some very interesting ICO I would invest some of the ETH. For example the ICO of Power Ledger in the past.

The Ripple-Technology is also used by the open-source-software Mojaloop. It is a project of the Bill Gates Foundation which reduces complexity and cost of building payment platforms that connect poor customers to merchants, banks, mobile money providers, governments.

Ripple is becoming more and more important.

Millions of germans are watching a morning tv news show on channel 2 every day. It is called "ZDF Morgenmagazin".

The co-founder of IOTA Dominik Schiener together with the chief digital officer of Volkswagen are invited next week to present and to talk about the IOTA project there. Many viewers will learn about it.

I will choose Waves because of the big potential of that altcoin. Waves has a great platform with a good and hard working team of developer.

Smart contracts and Waves NG update are coming soon.