Seagate Barracuda 3TB SATA Hard Drive
I'm a firm believer that you should always buy at least twice as much hard drive space as you think you might need. Nowadays the price differential is minimal and having too much is certainly better than running out of space down the road.
My suggestion for a big, fast drive is the Seagate Barracuda 3 TB SATA drive. Yes, it has a lot of space with 3 TB. Unless you are working with huge number of photos and/or video, you'll have plenty of space with some to spare. For those who feel it isn't worth the price if you won't use it, getting only a 2 TB drive will save you about $18. Is it really worth saving $18 to have to think about replacing the drive down the road if it fills up?
When I research drives, I'm always shocked at how low the prices are getting. This is a darned fast mechanical drive with a ton of space and it sells for only $120 right now at Amazon! If you are building a new machine or looking to upgrade your current machine, this is a drive you should seriously consider.