I was quite old when I started gaming, the first PC's I played games on where Pentium II and Pentium III computers that were formerly used by my mother, I don't know what graphics chip they had, but there was no gaming in mind when they were bought (by my father to use for office tasks by my mother).

The first one I bought for myself did have gaming in mind, Age of Empires II and Battlefield 1942 mostly, it was an Acer Aspire T120 with an Athlon64 3000+ single core processor and GeForce 6200 graphics. More advanced than the ones mentioned by other posters above, but it was already 2005 or 2006, if I remember well, when I bought my first PC.
I remember my first digital porn picture and it wasn't downloaded but I created it myself, with a kind of Paint program on the BBC Acorn of my father, back in the eighties, when I was a teenager. I made sure I kept the floppy I stored it on safe from my dad ;-).

Pentium 233 MHz
32 MB RAM
3 GB HDD

Estimated cost: 1600 dollars.

Edit: And if consoles do count, my first one was a Gameboy, followed by a Sega Master System. Both of them bought before my first PC.

My first PC was built a few years ago (I know, late to the party, only been using the Family's PC)
& I can't remember the specs :/

My first computer was a Commodore 64.
After that, i got an Amiga 500.

My first PC was a 486DX 50Mhz with 4mb Ram and a 125mb Seagate medalist harddrive, all hooked up to a 14" Svga monitor. Later i purchased a vl-bus based Ati mach32 accelerator to replace that crappy oak graphics adaptor.

Total cost for the PC back then was around $3200.

My first game system was a nes, whit mario bros (I was 3 years old), then was a PC, a 386 IBM whit MSDOS the games I use played on it were Prince of persia, Snoopy's Game Club, Grand Prix Circuit... I love these games...

Videopac aka magnavox odyssey 2. With, uh, a tv.

A shiny Atari 2600 with nice crappy games running on the living room TV.
Then came an Apple2 and an Atari 520STF (loved that one).
My first IBM 80286 with MSDOS came much later.

Yup, it's official, I'm old ;)

http://en.wikipedia.org/wiki/TK90X

Yup... I'm getting old...

Atari STF 1024 - if you count playing public domain games on a monochrome monitor, heh. Otherwise it's my current one, the first to actually have a decent graphic card (GeForce GTX660).

In before TinyE's obligatory innuendo about the typo in the thread title. ;)

First gaming rig: intel pentium 4 titan 2.0ghz, 256mb ram(512 after a few years), nvidia geforce 2 mx 400 mx 64mb 64bit ddr(after a few years nvidia fx 5500 128mb 128bit ddr2 i think).
Actual rig: e8200 2.66ghz, 4gb ram ddr2 800mhz, nvidia leadtek winfast px 9600gt 512mb gddr3 256bit(I don't plan in upgrading since I'll want to play only 2-3 more games like thief 4, dying light, hellraid, gta 5).

My first ever rig was a second hand system bought from a friend with the sole purpose of gaming:
AMD K6-2, 450Mhz, 128MB RAM and a Voodoo 2.

But MY real first gaming rig, one that I had constructed back in 2002 was thus:
MSI Neo2 865PE MB (Still one of the best motherboards ever made)
Pentium 4 2.8Ghz
512MB DDR1 RAM (A stupid cost saving decision on my part, fixed a while later)
Radeon 9800 Pro

And I'm still running this PC today, albeit with a Radeon HD3650, a larger PSU and more RAM, but everything it was still survives. Though it's now getting ready to be put out to pasture as far as gaming is concerned, it's been an incredible machine, ever stable and dependable, lasting longer than it probably should, the thought of retiring it actually makes me a little sad.

Can you believe I'm still using the original 120GB HDD? It's a Hitachi Deskstar, the very HDD that got nicknamed "deathstar" due to an overwhelming failure rate... yet mine has never, ever skipped a single beat in 11 years and it's still going strong.

She was a beauty!

My fist gaming rig is the Power Glove.

The first gaming rig was the very first computer I got. It was a no-name beige box with the following config:

CPU: AMD 5x86 which ran at max 133Mhz (basically a beefed up 486)
RAM: 8 MB (later 16 - might have been EDO, not sure though)
HDD: 1 GB Seagate (gave up the ghost after 1 or two years), replaced by a Quantum Fireball lct drive with either 5 or 10 GB of storage space
3.5" FDD
Video: a Cirrus Logic piece of sh** with 1MB of VRAM, later replaced by an S3 ViRGE with 4MB of VRAM
14" CRT Proview display that could do max 1024x768 interlaced so I ran it at 800x600 (60Hz refresh rate - oh my poor eyes)

Later it got a sound card with one of those OPL3 chips, a 33.6k modem (internal but it was not a winmodem) and a 24x LG CD-ROM reader which, after the warranty period expired, just died (piece of sh**)

Got me through the remainder of grade school, high-school and Uni. Things got better once I got a job :)