I think I'll just go through as many systems as possible to waste time, heh.
BBC Microcomputer (got around 1991 thanks to my mum's work upgrading to IBMs, my very first computer)
CPU: 2MHz 6502
RAM: 32KB
Video: 8 graphics modes, 8 colours
Audio: Four channels
Speakers: Integrated
HDD: None
Removable Storage: 5 1/4" floppy disks
Network: ECONET socket
OS: Acorn OS
Monitor: 10" colour screen
Viglen (bought around 1991, PSU is effed)
CPU: 486DX2 66MHz
RAM: 16MB
Video: S3 1MB
Audio: SoundBlaster 16/originally none
Speakers: SoundBlaster stereo/originally none
HDD: 110MB
Removable Storage: Quad-speed CD-ROM and FDD/originally just FDD
Network: None
OS: Windows 95 and MS-DOS 6.22/originally Windows 3.1 and MS-DOS 6.22
Monitor: 14" flickery Dell thing/originally 14" flickery Viglen thing
Dell No. 1 (bought around 1998)
CPU: 350MHz Pentium II
RAM: 192MB/originally 64MB
Video: nVidia TNT2 16MB/originally Matrox I think
Audio: TBS Montego
Speakers: Altec Lansing 2.1
HDD: 20GB/originally 7GB
Removable Storage: CD-ROM drive/had Zip 100
Network: 10Mbps ISA card/originally had none
OS: Windows 2000/has been Windows 98, 98SE, BeOS 5 and Mandrake 7
Monitor: 17" Dell
Dell No. 2 (bought around 2001)
CPU: 1GHz Pentium III
RAM: 512MB/originally 128MB
Video: nVidia GeForce 2MX 32MB/originally nVidia TNT2
Audio: SoundBlaster Live!
Speakers: Altec Lansing 2.1
HDD: 60GB/originally 40GB
Removable Storage: CD-RW and DVD
Network: 10/100Mbps PCI card/originally had none
OS: Windows XP Home/originally Windows ME
Monitor: 17" Dell
Home-built PC (built 2002, the one I use most)
CPU: 2.4GHz Pentium IV
RAM: 768MB/originally 256MB
Video: ATI Radeon 8500 64MB
Audio: SoundBlaster Audigy 2
Speakers: VideoLogic 5.1
HDD: 80GB and 7GB
Removable Storage: CD-RW and DVD/had Zip 100 also
Network: 10/100Mbps integrated and wireless-enabled
OS: Windows XP Home and Slackware 10 dual-boot/also tried dual-booting with SuSE 8.1, SuSE 9 and Fedora Core 2
Monitor: 17" Mitsubishi
Dell Laptop (mum's, bought 2004)
CPU: Pentium-M 1.6GHz
RAM: 1024MB
Video: ATI Mobility Radeon 9600
Audio: SigmaTel something-or-other
Speakers: Integrated stereo
HDD: 60GB
Removable Storage: DVD-RW and CD-RW
Network: 10/100Mbps integrated and wireless-enabled
OS: Windows XP Professional
Monitor: 15.4" TFT
And that's more or less it.
Unless you want me to have a look in the loft, of course...