What are the secure Hot wallets to store altcoins for long term?
Most of the bounty campaign here in btctalk recommend to use myetherwallet because it supports many types of coins. If you have an extra budget you can go for a hardware wallet for more security.
I think coinbase would be a good option for you. Since coinbase is considered as one of the most trusted wallet in this kind of business.
Coinbase only support bitcoin,litecoin and ethereum coin and doesnt support an erc20 token so its not good for storing altcoins.