Edited for your sake
I found it relevant to add my Wishlist to this thread because it consist of the games which I'm going to buy in the future

I've brought 8 so far:
Spellforce
The Guild
Beneath a Steel Sky
Ishar Compilation
Deciples
Fantastic Journey
Big Race USA
Timeshock (yes I got pulled in by the pinball promo)
Soon to have 9 as I won a gamecode from Geeks, still trying to decide but I think I'll go for Gothic. .

I'm up to like 10 I think? Something like that.
It would be a LOT more if I had more time in the day to finish the games I own.

Not counting the free adventure games, I've made 19 purchases.
Spellforce
Shattered Steel
Tom Clancy's Rainbow Six
Tom Clancy's Ghost Recon
Freespace
Freespace 2
Sacrifice
Earth 2140
Second Sight
Shogo: MAD
Tex Murphy 1&2
Simon the Sorcerer
The Feeble Files
In Cold Blood
Gothic
Gothic II
Disciples
Disciples II
Septerra Core
Besides that, there's some games I own in the GOG catalogue that I didn't buy from GOG:
Arx Fatalis
Fallout 1
Fallout 2
Fallout Tactics
Beyond Good and Evil
So, in total, I guess I have 30 GOG games.

Fallout 1, 2 and Beyond Good and Evil rocks:)

So far:
Fallout
The Nations - Gold Edition
I have plans to purchase many, many more... GoG is just plain, freakin' awesome!!!

I have 55 games in my account (58 with freebies) at the moment.

My collection it's little, have to spread money between classics and new retail titles :-). For now 10 games + 3 free ones
Colin 2005
Fallout Tactics
Freespace + Expansion
Freespace 2
Graound Control Gold
Haegemonia Gold
Oddworld Abe's Oddysee
PP Fantastic Journey
Sacrifice
Toca RD 3

Not so many. Only three (Fallout 2, Giants Citizen Kabuto and that one free game, Beneath a steel sky), to be exact. But the instant they release Heroes of Might and Magic III, Homeworld (all of 'em) and Roller Coaster Tycoon I will beg them to take more of my money.

I've bought around 25 games...
All games I couldn't get my hands on during my childhood.

OBSCURE
HAEGEMONIA GOLD EDITION
REDNECK RAMPAGE COLLECTION

STONEKEEP
SACRIFICE

GIANTS: CITIZEN KABUTO
ARX FATALIS
BENEATH A STEEL SKY
TEENAGENT
FALLOUT
EARTHWORM JIM 1 + 2
LURE OF THE TEMPTRESS
12 (3 of them free)

Slowly building up the collection.
Freespace 2
Flatout
Painkiller
Lords of Magic SE
Evil Genius
MDK
Duke Nukem 3D
Fallout
Fallout 2
Fallout Tactics
Lure of the Temptress (Free)
Beneath a Steel Sky (Free)
Duke Nukem Manhattan Project
Kingpin
Septerra Core
Pro Pinball Fantastic Journey
Teen Agent (Free)
Ghost Master
TOCA 3
Capitalism Plus
Capitalism 2
Seven Kingdoms
Seven Kingdoms 2
Warlords III: Battlecry
Second Sight
Hostile Waters: Anteaus Rising
I was a bit silly this weekend lol

I've reached 27 with this weekend promo (of course some games are packages with multiple games...)
Lure of the Temptress (Free)
Beneath a Steel Sky (Free)
Teen Agent (Free)
Megarace + Megarace 2
Rise of the Triad: Dark War
Blake Stone: Planet Strike
Blake Stone: Aliens of Gold
1nsane
TOCA Race Driver 3
Mean Streets + Martian Memorandum
Colin McRae Rally 2005
Descent 1 + 2
Freespace 2
Descent 3 + Expansion
Castles + Castles 2
Redneck Rampage
Stonekeep
Freespace + Expansion
Earthworm Jim 1 + 2
Jagged Alliance 2: Unfinished Business
Lionheart: Legacy of the Crusader
Die by the Sword + Expansion
Giants: Citizen Kabuto
MDK
Messiah
Ishar Compilation
Robinson's Requiem Collection
Next up are probably Imperial Glory and the Incredible Machine Mega Pack... oh yeah, I LOVE GOG :D

3: Duke Nukem 3d, BG&E, and the original Stronghold. Love them all, especially BG&E.

Twenty two premium titles at present. But 8 of those were free in BOGOF promotions.