My best component is my ageing MITSUMI keyboard........
Why??
Its the only part of my PC that has never been replaced.....It has seen over 5 generations of CPU, countless motherboards, and not to mention survived severe physical trauma (i have hit this thing so many times, that I am amazed it still functions at all, spilt coke, coffee and all manner of foods onto it, and even threw it out of the window once!)
Oh, and another thing......its the only part of my PC that I never actually bought!!! Not bad for a freebie...