What makes you build a system around an amplifier?

Serious question. I almost always care about the room and speakers first, then build around that. However, this is not the only way to do things.

If you have ever insisted on keeping your amplifier, but were willing to change everything else around it, please let us know why. What made an amp so outstanding in your mind that it was worth making it your center piece. Imaging? slam?

Be specific about the amp and speakers or other gear that you shuffled through.

Thanks!

E