Too many to count. But there are some I remember.
All were given to me or my family, or bought used, except for the Acer desktop
Current:
Desktop 1 - Self Built, 2.4 GHz Intel P4, 1.5 GB RAM, 320 GB HD, nVidia 6800, Win XP Pro
Desktop 2 - Self Built, 1.8 GHz AMD Athlon, 1 GB RAM, 40 GB HD, nVidia 4200ti, Win XP Pro
Laptop Toshiba, 1.73 GHz Intel Celeron, 512 RAM (1.5 GB soon), 80 GB HD, Intel video, Vista
Commodore 64 + original monitor, 2 disk drives, tape drive, modem, and printer.
Retired:
2 Commodore 64's (one has no sound and the other is missing a key)
Laptop - Compaq LTE5380, 133 MHz Intel P1, 48 MB RAM, 2.1 GB HD, 8x CD-ROM Win 98
Laptop - Compaq LTE5280, 90 MHz Intel P1 (RAM, HD, and CD are in the LTE5380)
Desktop - IBM Netfinity, 2x 233 Intel PII's, 384 MB RAM, 4.6 GB HD, 8MB ATI vid card, Win XP Pro
Desktop - Dell, 400 Mhz Intel Celeron, 256 MB RAM, 12 GB HD, 8MB ATI Vid, 24x CD-ROM, Win 98
4-5 desktops, AMD Athlon and Intel PIII, in various stages of disassembly for salvage.
Past:
Commodore 128 (R.I.P.)
Desktop - IBM PC Jr.
Desktop - IBM PC XT, 4.77 Mhz Intel 8088, 640 KB RAM, 20 MB HD, PC-DOS 2.0
Desktop - Compaq Deskpro 286, 16 MHz Intel 286, 1MB RAM, unknown HD
Desktop - IBM PS/2, 33 MHz 386DX, 4 MB RAM, 80 MB HD
Desktop - Self Built, 40 MHz Cyrix 486 DX4, 8 MB RAM, 400 MB HD, 1 MB video card, Win 3.1
Desktop - Compaq, 66 Mhz Intel 486DX4, 8MB RAM, 430 MB HD, 1x CD-ROM, Windows 3.11
Desktop - Acer, 60 MHz Intel P1, 8 MB RAM 730 MB HD, 2 MB video card, 2x CD-ROM, 14.4k modem, Win 3.1 -> Win 95 (Bought new Mom and Dad payed $2500 in 1994)
Desktop - Dell XPS P90, 90 MHz Intel P1, 64 MB RAM, 1.2 GB HD, 4 MB vid card, 4x CD-ROM, 33.6k modem, Win 95 -> Win 98
Desktop - Packard Bell, 233 MHz Intel P1 MMX, 128 MB RAM, 10.0 GB HD, 8 MB vid card, 24x CD-ROM and later 56x CD-R, 56k modem, Win 98
And many others...