Very very first:
Sanyo MBC 550
Not PC compatible, not even ISA (no slots, was stuch with either monochrome RCA output or the 16 color CGA-esque round DIN video out.
Could not run any games, not even simple ones like Montezuma's Revenge.
8088 @ 3.58 MHz
256k RAM max
no hard drive
dual 360k 5.25" floppy
I was probably 7 or 8 at the time, learned to program in BASIC and unfortuneately I was stuck with it and couldn't run any commercially available C compilers... I was stuck with this machine through highschool until I was old enough to get a job and buy/build my own (ie: 16).
So while everyone else was playing Doom, Quake, etc. on their top of the line 486 and then brand spanking new Pentium 60/66 PCs, I had this...
Being poked fun at then might explain now why upgrade every time something new comes out. Quad core + SLI for the win!
The first PC I built with my first job with my first few paychecks at 16 (1995):
Pentium 200 Mhz (just came out)
32 MB SDRAM (SDRAM was brand spanking new, everyone else was using EDO and FPM)
Diamond Stealth 64 4M
Monster 3D 3Dfx Voodoo 4MB
Soundblaster AWE32
1.6GB WD HDD (fastest available at the time)
Yeah that was my revenge for that green screen 8088 I had to endure in highschool hehe. It was then what a Core2 Quad + 8800GTX SLI is now It was worth being the first and only one amongst my friends and peers to have transparent water in Quake and be able to run it at 640x480... no more green monitor for me =D
Strangely... being an experienced programmer now, I enjoy playing with old school and limited capability hardware. Wouldn't mind a Apple IIgs or a Atari 800XL, got lots of 65816/6502 experience from the SNES days.