First Computer would be a 1984 Amstrad CPC464, but keeping to PCs:
October, 1994: Packard Bell Intel 80486 SX 50MHz, 4mb RAM, 340mb Seagate HDD, 14" Monitor, later added a Quad speed CDROM and Sound Blaster 16 which cost £264. Printer was a Citizen ABC 24pin Colour Dot Matrix.
Upgraded this PC to a DX2 66MHz, 24mb RAM, 1gb WD HDD.
Built new PC August 1997: Intel Pentium II Klamath 266MHz @ 300MHz (cost £550 in the month of release), Tyan Tahoe 440FX Motherboard, 48mb 70ns SIMMs, 6.4gb Seagate HDD, 24x Matshut
a CDROM, SB16, Full Tower Case with Seasonic PSU, Matrox Millennium II 4mb Graphics + Guillemont Voodoo2 12mb (added month of release).
Then i think it goes upgrade to 440BX motherboard and 128mb RAM, Celeron 400@500, then P3 Coppermine 500 @ 750 in a different motherboard, then Duron 800 @ 933MHz with Engineering Sample DDR, then P4 1.6GHz then P4 2.5GHz with 768mb RDRAM then A64 3000+ @ 2.3GHz and now this Opteron @ 2.75GHz.
The Packard Bell 486 which despite requiring a new BIOS chip soldering in to beat the Millennium Bug, is still going, and can boot into Windows 3.11 as fast as my modern PC can into XP.