First game you ever bought on steam?

25 Nov 2011 - 2,99€ - SSHD Double Pack (ROW) - Refunded

26 Nov 2011 - 3,99€ - Serious Sam Gold Pack (ROW)

19 Feb 2010 Aliens vs Predator Retail

L4D

May 23, 2009 $29.99 Counter Strike Complete :)

CS:S + Garry's Mod bundle, Oct. 22 2009

It's not accurate for me.

I've had a Steam account since prior to HL2's release, when Steam came out of Beta.

But in my transaction history, it lists this as the first one:
December 2006 - Prey Retail

Either I've purchased so many things that it can't show back further than that, or that's when it started recording the transaction history. Too bad :(

All my games have been donated to me by friends or won from giveaways. :D
The first (and only) Steam purchase I've made though was RAGE for my cousin.

21 Jul 2011$9.99Purchase
Terraria

12 Dec 2010FreePurchase
Prey Retail

1 Oct 2010FreePurchase
Half-Life Platinum Pack

Member since: August 22, 2007

26 Dec 2011 2,24€ Purchase Nation Red

6 Jul 2011 $6.23 Killing Floor Bundle - July 2011

28th may 2007, counterstrike.

My purchase history still isn't accurate (it says my first purchase was 2006, but in fact it was earlier), but my Profile at least has my Member Since date right:

September 21, 2003

Killing Floor Bundle - July 2011

Killing Floor Bundle
Member since: February 5, 2010

Dec 21, 2009:ATI Half-Life 2: Deathmatch / Half-Life 2: Lost Coast Promo

Member since February 18, 2008

Garry's Mod, The Orange Box, Audiosurf, and PvZ on Aug 1, 2009. But I got Portal: The First Slice Mar 5 2008.

my first steam game was left 4 dead 2 ~ 2011

I believe technically it was the collector's edition of HL2.

registered 7-21-09
1st game in library - Portal First Slice (freebie with NVIDIA card) 8-2-09
1st actual purchase - F1 2010 3-26-11

and now I can't freakin' stop - damn you Steam and your sales!!

half life 1 + cs 1.6

good old days

Red Orchestra, October 2006

Member since December 30, 2009, bought Garry's Mod on November 27, 2011

17 July 2010, HL2.

I remember begging it the hell off my mom's nerves, just so I could play mods.

Heh.

Member since: February 3, 2011

Mar 18, 2011 $29.99 Purchase: The Orange Box