That is my collection.

Sony Vaio PCG-505TR. My favorite old device. Literally haven't seen computer more accurate and cooler then that for 1998!
Pentium MMX 300Mhz. Yes first generation - 300Mhz, it exists.
128 MB Card RAM (maximum for that laptop I believe, anyway I pulled it from other non working laptop, the same model)
NEOMagic MagicGraph 128XD 2MB
Transcend 32GB SSD (recognized in Bios as 8gb, but who cares?)
ESS Audio Drive + Roland Sound Canvas (Serial connection)
New batteries there! finally can use it everywhere
Kinda the main retro machine.

PowerBook G3 (bought it almost for nothing on craigslist along with Compaq above)
PowerPC 300Mhz
192 MB RAM (512 on the way)
ATI Rage PRO LT 4GB
Sandisk 8GB UDMA CF-IDE (working as fast as possible)
Sound board is wonderful there. Virtual MIDI without any issues, no delay on MIDI keyboard! Well, apple, as always for musician.

Compaq Elite LTE 4/75CXL (I wished for 486 Laptop like last 2 years, bought it on Craigslist like for nothing. Bad HDD only was there, replaced and Floppy is dead, belt is totally broken, hard to find though)
Intel 486 75Mhz
16MB RAM
Western Digital Video 1MB
Toshiba 6GB HDD (pulled out from Sony Vaio's Donor, with some bad secotrs). It came with old fashion fat 2.5 HDD, don't know even the size of that thing, cannot properly start.
Covox Speech Thing (on the way)
Roland Sound Canvas 55ST (serial, shared with Sony Vaio)
Love this device, looks like Desktop for customizing, except Video. Everything you can replace there.

Roland SC-55ST itself. Serial + Midi connection.
Finally, I can enjoy Wavetable in DOS games. Windows programs and games are also good. I even use it for Sibelius program to play music, through the USB to Midi connection.

All that stuff connected to KVM switcher, except PowerBook (waiting for PS/2 to USB converter to finish). All sound connections connected to the mixer. Waiting for serial switcher for my Roland as well.

Also I have PCMCIA cards/devices:
CD-ROM VAIO 16-bit (works on both PC laptops, not Mac or I miss the drivers)
SD Reader (works everywhere)
CF Reader (works everywhere)
USB 2.0 NEC series 32-bit (works DOS/Windows on Vaio and Mac as well. no Compaq as it 32-bit)
ASUS Wi-Fi CardBus 54Mbit, 32-bit (actually too heavy for Vaio and doesn't work on mac, worked on different Pentium II laptop, just in case. no Compaq as it 32-bit)
Linksys WPC11 ver3 11Mbit, 16-bit (works everywhere, No WPA-SK though, only open networks or old fashion encryption and Mac Drivers are shareware)
3Com Megahertz 10/100 Ethernet card 32-bit (works on Sony Vaio, haven't tried Mac though, no Compaq as it 32-bit)