I'm sure this has been asked 100 times, but would getting a black benefit game performance, or is it jut a case of starting up the computer and applications quicker, because a 5 second longer start up doesn't worry me.
Western Digital Caviar Black HDDs have better read and write speeds, so for data intensive things the Western Digital Caviar Black gives a better performance than a Western Digital Caviar Blue. The Western Digital Caviar Blue is good for storage, and all kinds of basic usage.
So basically, you'll have faster loading times with a Western Digital Caviar Black.
Black drives come with a 5 year warranty as opposed to 3 on the blue drives. So you'll get a bit of extra speed (whether or not in the real world you'd really notice much of a difference is another matter) and an extra 2 year warranty. It all comes down to the price premium of the black drives, is the extra 2 years warranty worth the cost to you as i doubt you'd really notice any difference between the 2 in day to day usage