Toshiba and Intel (separately) are talking about 10 TB solid state drives available in 2016. Their new 3D chips will make this possible in a 2.5” form factor, popular in laptops.
The advantages of SSD devices are speed, size, weight savings, durability, less noise and the fact that they don’t have to be defragmented. Historically, SSD’s have been more expensive than rotating platter disk drives, but as per usual, as the technology matures prices should be more competitive.
Eventually, much of the big data we use routinely (movies and music) will be stored in the cloud, but for fast, local processing you can’t beat SSDs.
So, my advice: if you have a choice and can afford them, choose SSD’s over rotating platter HDD devices.