For a newish system, yes. It depends on how much you value load times for windows and games. An SSD for system and Caviar Black for storage would work well if your budget suits.
You can connect it via sata. From what I'm reading (I've not used one) The drives are low-end performance wise (compared to good SSDs) but much better than mechanical disks. There are some bonus features such as the way it stores data to provide redundancy and internal TRIM support. Thats about as much as I can give you on that. Here is a couple of reviews to help you though.