As said before, if the block sizes change, they won't be immediately filled up to the top, so the blockchain won't start to grow at a faster pace all of a sudden. But I do approve of new disks for nodes, it will make them future proof!
That being said, I've also had bad experiences and bad feedback from Seagate. Maxtor isn't bad, but if you can go for WD, go for it. As for Hitachi, never used their drives, so I cannot vouch for them, but I've heard they have amazing drives