What is the first Store Transaction entry on your account?

Steam Store
Orcs Must Die!

May 12, 2010 Portal - Complimentary (Opt In)

brofist

Garry's Mod was the first thing I actually paid for though. Been playing it ever since.

Steam - Complimentary

And when it comes to games:

Half-Life 2 Classic - Retail

Dirt 3 Retail. First purchase is Skyrim.

Morrowind Game of the Year - Steam Store

27 Dec 2009
$4.99
Purchase
Torchlight

Jun 30, 2011 $4.99Purchase
Dwarfs!?

Mine seems to be July 11 2012, bought Dungeon Defenders and a ton of DLC for it. Yeah, I haven't been in Steam for a long time yet. DunDef actually is the game that convinced me to join Steam, I played it a lot in local co-op with a friend of mine, and I decided I had to have a copy of my own. :3

Dota 2 - Hardware Survey

Half-Life 2 Retail Collectors Complimentary

I'm pretty sure someone paid for that at that point ;D

• 11 Oct 2012 | Gear Up | Free

September 9, 2010 - The Orange Box Retail
December 21, 2010 - The Rockstar Collection, Bethesda Holiday Sale 2010 109,98€ :-o

The Orange Box Retail, April 19 2009

7 May 2009 ATI Half-Life 2: Deathmatch / Half-Life 2: Lost Coast Promo - Purchase (Free) [wut]

First game I got was retail Orange Box during January 2008, but it's not shown there.
First purchase was Recettear, 24 Jun 2011.

Half-Life Platinum Pack / Orange Box

Portal 1 for free in September 2011.

Sep 26, 2009 $9.99 Purchase
Garry's Mod

Still love it to this day, this is the oldest tracked game... I know I had some before this.

Left 4 Dead. Everything before that was retail keys redeemed.

Summer Sale Prize - Alien Breed 2 :DDDD

Killing Floor Bundle

KILLING FLOOOOORRRRR!!!!!!!!

Same as OP.

First thing I bought was Left 4 Dead bundle and TF2

Jan 10 2008: NVIDIA Portal: The First Slice

24 Dec 2009 | Audiosurf | £1.50

'Valve Complete 2008 Pack' for a LAN-party. Same people meet once every year and game it out, and actually just got back from this year's.

Can still feel the toll it's taken on my somewhat aging frame ^_^