"Sennheiser Sampler"
Play in HD for best audio! I finally dug out my old neglected pair of Sennheiser HD 600 headphones and replaced the disintegrated ear pads. The result was a stunning audio feedback from my laptop, even without an amplifier!
EDIT: Comparing this video with another, even as recent as my Valentine's Day post, I can already hear a greater dynamic range, enabled by being able to pick out much softer sounds when I press the keys softly. I will be getting an amplifier for the headphones soon, hopefully that would improve the quality even more!