I have bought Invisible War four times.
My first copy got scratched beyond repair, so I bought a second one.
I bought it a third time on Steam so I could play it without a CD.
And today, I bought it in the bundle here on GOG so I can have it DRM-free with goodies.

Despite its many, many, many flaws... I still love this game.

Two times. The ones where I cannot find the CD anymore - I rebought them from GOG.

Let's see, I have the Genesis copy of Sonic 3, the PS2 collection version of Sonic 3, the Ultimate Genesis Collection version of Sonic 3, the XBLA version of Sonic 3, the Steam version of Sonic 3 from the Genesis Collection and the Genesis Gold Collection version of Sonic 3.

I-War 1 three times.

Bought, didnt understand and returned. Later bought again and really wanted to understand it after all - and loved it ever since. Later ofcourse had to buy from here as well as i dont really care for the physical media anymore :)

well, thats intentional buys. If i counted all the unintentional bundle doubles/triples/quadruples and friend buys i wouldnt know.

Maybe Blood Bowl - i think i actually bought 6 copies of it for friends (at discount). So if you count like that - around seven copies perhaps?

I've got a list of games I've bought multiple times, sadly... Sometimes when the games were in plain sight. I feel like a hoarder.

Diablo, bought a total of four seperate times, all original copy discs.

DIablo II, bought a total of three seperate discs, this time the expansions.

Heroes III, bought a total of four times, one as a bundle after the first three CDs were too old.

Baldur's Gate, bought a total of three times.

Dungeon Siege, bought a total of three times... All discs.

Probably Pikmin 2. Back when I first got my GameCube, I must have bought, sold, and rebought it at least three or four times. I think once it burned in my housefire XD

On my laptop, I have Postal 2 on Desura, Steam, and direct download (via my friend's CD). I usually only play the Steam version.

The game I have the most copies of is Fallout.

Before I had internet:
1. From a gaming magazine
2. It came together with Fallout 2
3. It came together with Fallout Tactics (and Fallout 2)

Internet!!
4. I bought it on GOG so I can play it in english.

Sid Meier's Alpha Centauri
Bought the original game.
Bought the game & expac combined.
Bought it on GOG.
Bought 17 gift copies here for various reasons....

I've purchased TES IV: Oblivion four times. My Xbox 360 ate my first two copies of it, then I bought the GOTY edition for Xbox and later bought the GOTY on Steam.

I've purchased Fallout 3 four times also. For Xbox 360 I purchased the Collector's edition on the day of release, lost my copy some time later, so I repurchased it. Then all of the DLC came out so I bought the GOTY edition. Finally, I purchased the GOTY on Steam a couple years ago.

I have 5 copies of Quake 2.


edit:
* original copy x1
* copies purchased as part of various used game lots x2
* bundled with Quake 4 retail release x1
* steam id bundle x1

Gothic 1.

- bought the disk
- bought it with a magazine
- bought another disk since first got destroyed (stepped on it while being drunk)
- received it as a b-day gift (if that counts)
- bought it with Gothic Universe Edition (someone stole it from my backpack on my way home :[ that very day)
- bought the disk as a gift to a friend (who introduced me to Gothic series)
- bought it on GOG

I've bought StarCraft (the first one) three times. My first disc exploded in the dvd-drive, destroying it in the process. So I thought "Oh well, it is a good game so I'll just get another disc" and bought a new copy. I open the new cd case and notice that it is one of those that doesn't have the button in the middle that makes the cd pop out. So I carefully try to pry the cd out but, alas, it was not to be and I hear the noise of a crack appearing in the plastic. Off I go to the store again and I'm told they can't replace it so a new copy it is.

Other than that I've bought Knights of the Old Republic twice and Deus Ex twice, bought the first copy on steam before I knew of gog and I really wanted the soundtrack gog offered.

psychonauts
1.retail
2. steam
3. gog
4. humble bundle v
5. humble double fine bundle

and i gave hb bundles 10+, so i count them :D

I have 3 copies of UFO: Afterlight.
1st copy is a retail collection of the 3 UFO games. UFO: Aftermath cannot be installed unfortunately, due to a bad sector on the disk. The other 2 games work fine.
2nd copy is from GOG. In November 2011 1C catalogue was on promo (60% off) and I jumped at the chance to have a proper working copy of the UFO:A? games.
3rd copy is on Steam. UFO:AL was included in a bundle and since I didn't already have it on steam, I added it.

So what does my 3 copies have to do with the games industry?