Welcome to the community, Teo Lakis!
It really depends on what you want to use the drive for as @Conrad Pinto already mentioned.
I guess the 1.5 TB external you are speaking of is WD Elements, which I personally like very much because it's fast and has no hardware encryption and it's pretty comfortable to carry around with you all the time.
http://wdc.com/en/products/products.aspx?id=470
If you want additional secondary storage to put into your computer or in an externally powered enclosure, you can take a look at WD Green drives. They are very quiet and run cool, pretty reliable as a storage solution for your massive data as well. The great thing about these ones is that they can be used in external enclosures for storage without...