There is no “best” long term harddrive that you could buy from Amazon. They all SUCK for this purpose. There is not a single harddrive on Amazon which is suitable for long-term storage. Never store anything important on a harddrive without a backup. Any hard drive can - and will - fail without warning, regardless of age, brand, make, or model. You can buy a RAID appliance on Amazon which is SOMEWHAT suitable for this purpose - it has several harddrives, and redundantly stores the data, so that if one fails (or more, depending on the configuration) you can just pop another drive in and nothing is lost (though too many failed drives destroy the array). However, such a system is still useless if your house burns in a fire or has a massive power surge.
BUT You probably already have the absolute best archival hard drive in the world, which is absolutely guaranteed to NEVER lose data (even if your computer is physically destroyed). This drive (which you probably already have) offers absolute 100% assurance of reliable data recovery “forever.”
Of course, I’m talking about Google Drive, or Dropbox, or Azure, or any of the many online storage services. You probably already have a basic account on at least one of these types of services (they’re free, and fairly generous).
You cannot lose data stored in these cloud drives. Your data is stored under pristine conditions (perfect power, temperature, etc) in massively distributed and redundant datacenters, in RAID-10 storage racks which are constantly and diligently monitored and serviced 24x7 by skilled professionals.
Your data is absolutely safe and secure. Nobody but you can possibly access it. It is stored in encrypted form, and only you have the decryption keys. Your computer decrypts the data as it reads it, and encrypts it as it writes it. Anybody who is able to access your data in the cloud (or in-transit) without the decryption keys will see only gibberish which is impossible to unscramble.
You can make these drives appear just like any other hard drive, with a drive letter and everything else. Performance will be reduced due to internet latency, but you don’t care about that if you’re just doing long-term storage. It can take all night (and it might), but you don’t care.
You would obviously not want to install a game onto an internet storage device. The game performance would be abominable.
If you don’t care about the convenience of having the storage available as a drive-letter then you can use one of the many online backup services, such as Carbonite. They offer the same level of data protection and security, though it is more of a hassle if you want to actually recover anything. They are really designed more for backups then archival storage. And those services are much better than using your own backup media, since your own media can still be destroyed in a house fire (or otherwise lost/damaged), and the long-term stability of your own media is probably doubtful (a DVD-RW, for example, is NOT good for archival storage; it’s not like a real DVD).