PowerMac Quad G5
Oh yeah, I always wanted one of these, but couldn't afford one (until now, used, and several years old).
When new, this machine was a digital monster, eating up anything you could throw at it. And now, many years later when it should be obsolete, it is still a powerhouse and quite useful if you're running older software (which I am, and will, for quite some time).
Easily expandable, super easy to open and maintain. The cooling fans are variable-speed, and vary from quiet to somewhat intrusive (under full load--all four processors kicking digital ass at the same time), but this generates heat when working hard, and the fans are needed to remove that heat. In fact, this is one of the first (if not the first) home computer to use a liquid cooling system. Impressive, but watch out for leaks, which will ruin the processor core.
If found at a good price, this is still a fantastic computer worth using even today (2016)!
Verified purchase: YesCondition: Pre-owned