Blue regular desktop use, not as fast as a black, for regular desktop use.
Red is for raid only, as error correction is not the same as a desktop.
RAID dose it's own error correction
For a boot disk, green wouldn't offer good performance. As the other poster noted, there is a "black" line which offers the highest performance but may cost a bit more. Generally Blue is pretty good.
Especially if you are using an SSD in your system for the OS, the blue is more than enough for standard storage. No need for a black in this case, imo.
You won't notice much of a difference in performance in gaming between a blue/black. Minimal. If you are a computer enthusiast who wants top performance and have the money to spend, black is the way to go, but if you are on a budget, the blue is fast enough for the job.