My first computer was a Sinclair ZX81, though I did have access to a ZX80 in the computer studies class at school and I did, once, play with an Acorn Atom owned by an uncle.
I eventually got a Sinclair ZX Spectrum 48k, to which I added the Interface 2 (ROM cartridge and joystick plug-in), Interface 1 (added serial ports and a connector for the Microdrive) and a Microdrive (a little tape based cartridge storage system offering a huge 100k of storage space!
Next I got an Atari STFM (when the price came down to £299 and it was available in WH Smiths) and that kept me going for a few years, but eventually I had to move to a Microsoft system of some sort and I got a Packard Bell 486 based machine for a (now) ridiculous price (on, admittedly, interest free credit) from a local department store. Seriously, I wince when I think back to how much that computer cost - the best part of £1500. It had a HUGE 256mb hard drive - that's Megabytes, not Gigabytes; I have USB sticks that have more storage capacity now.
That was running Windows 3.1; I got onto the Windows 95 Beta test and eventually (when my Beta version expired) upgraded to the full product.
From there it's been Wintel or WinAMD all the way (with a couple of slight diversions - I picked up an Apple IIE when it was being junked at work, and more recently a friend gave me an Apple Mac G4 which was being disposed of in similar circumstances)
The current set up is a self-built AMD Athlon 1100 with 512mb RAM, a donated eMachines thing running XP Home on a Pentium 4 1.5Ghz with 1.25mb RAM, the aforementioned G4 (MMD case, 1.25Ghz processor and 512mb RAM), a Fujitsu Siemens laptop with a 450Ghz Celeron processor that I built out of the working bits of two laptops. I also still have all the aforementioned computers somewhere, plus a couple of other bits and pieces (I have a Tulip 286 B&W laptop running Windows 3.1, and there is a DOS running Toshiba T1100 laptop that worked the last time I plugged it into the mains!
I also have a Handspring Visor Deluxe PDA which suits my portable purposes admirably well (and on which subject I will be posting later...), one of the very first 1st Generation Apple iPod Shuffles to arrive in the UK (courtesy of a generous friend and a 40th birthday!)