Depends how often and how quickly you want your data back.
Tapes are still a thing: $5-$10/TB (compressibility is a factor) will sit on your data until 2050 but it's a bit of a pain trying to remember what's where unless it's time-based data (plus a few thousand for the drive, but at least they will fit in a normal PC case).
For a a local disk-based system I'd slap 7x10TB (or 6x14, or whatever adds up nicely) into a NAS, set it to raid 6, and hope someone else was buying. I like Synology boxes, but I'm sure someone will be along shortly to say they're crap. Such is life... With that much data you are going to have to do some config, but it's not rocket surgery.
(Raid 6 gives you double redundancy, which can be a factor with a new system: The chances of two identical new drives failing at the same time is higher than I'd like. If it's a mission-critical system I'd be asking for a tape back up as well, if only to cover my ass when it all goes bang.)
The third option, if you only need to keep it for emergencies (say, disaster recovery) is chuck it onto the cloud. AWS (for instance) will keep your 45TB very safe, forever, for peanuts. The downside is that downloading it all back would bankrupt a small country so don't make a habit of it.
Edits for words, it's too early here and I need more coffee.
Another edit after more coffee: If it's an archive, rather than a production system, I'd go with standard drives and buy a spare with the savings, I don't think you'll see a benefit with "enterprise" specs. And for what it's worth, I don't feel there's a lot, if any, difference between the main drive manufacturers. Toshiba, Seagate and WD are all good.
