AVOID the WD Blue drives. Western Digital puts a very short head parking timer on their 5400 RPM drives. They will park their heads after something like 10-15 seconds of inactivity. When the OS needs data off the drive, it's forced to wait for a split second while the heads unpark. This can cause stuttering in games, and if your pagefile is on the drive it can cause the entire OS (including the mouse pointer) to freeze momentarily every time the drive has to unpark the heads to access the pagefile.
I initially thought the issue was limited to WD's 5400 RPM laptop drives and Green desktop drives. But I've seen at least one report of the issue from the owner of a 5400 RPM Blue desktop drive. At this point, I would only trust the...