Your First Steam Purchase

The Orange Box, way back in 2007.

Deus Ex Human Revolution.
Absolutely loved it.

Killing Floor
Great game.

Half Life 2 Episodes 1 & 2 and deathmatch

deja vu thread - Shogun 2 for me.

Skyrim

Garry's mod + TF2 bundle if i am correct

half life 1.

TF2

Terraria when it came out. My friends made me buy it on Steam and I'm glad that I did.

Counter-Strike Global Offensive

Counter-Strike (1.6), Half-Life and a few other games on GoldSrc engine in pack.

Serious Sam BFE

Would that be the first purchase from the Steam store or the first game I ever bought that was redeemable on Steam? Actually it doesn't matter. The first game I bought on Steam was from the Steam store, Rome Total War.

Civ V, really enjoyed playing it.

Left 4 Dead 2 :(

Counter-Strike Source!

Portal 2 awesome game

Valve Complete 2009 Pack

By Steam store it was Left 4 Dead 2, but first box with SteamWorks was Zeno Clash

Heroes VI

Condition Zero and Post Apocalyptic Mayhem - 10 Jul 2011. it took me over 4 years to buy my first game on Steam :D:D (Member since 21 January, 2007)

8 years ago...some sort of limited Valve collection that got me CS:CZ, CS, CS:S, and Dod:S.

Alpha Protocol was the first game I purchased from the Steam store and I still haven't played it yet:p