Apple Quadra 900
I was extremely lucky to find this one listed on Craigslist. It came from another collector who simply had to make room for something else. I drove out to pick it up on a very icy day, and I somehow managed to con a colleague into joining me on this adventure. I also put him to work carrying it out to my car. It is in excellent condition, and happens to be one of the few Macs capable of running A/UX 3. My favorite part of this system is the ridiculous key for the power button.
Getting that to install was an adventure unto itself, requiring me to find a specific model of SCSI CD-ROM drive. Maybe some day I'll make an OS or Software Screen Shots section of this site.