My Skate disc got a crack in the middle. I tried to use EA's disc replacement facility, but in my country all they would do is sell me another copy of the game. I waited for it to go cheap, and bought another copy then.

I ended up with two copies of The Legend of Zelda: The Wind Waker after spotting the gold box version for £5 in Gamestation. Gave the normal version away soon after.

I also had to replace Mariokart: Double Dash!! after losing the disc, and days of searching turned up nothing. I found it months later when I tidied up to redecorate.

Oblivion: The disk broke and my girlfriend had just formatted her PC, bleh.
Neverwinter Nights 1 & 2 + expansions (His & hers copies for multiplayer :P)
Final Fantasy VII: Disk 1 broke due to being overplayed
Half-Life 2 & Ep1: Bought the Orange box after buying these seperately. Still could give them away as gifts.

I have the same game for multiple systems. This was much more common in the classic days when the same game (or a variant of it) might appear on half a dozen or more platforms.

In recent times, I have bought the same game for PS2, GC, and Xbox (Intellivision Lives). I also different Zelda collections on the GC that were on the N64 or even the NES. Finally, I bought Kirby's Adventure VC of the Wii, even though I have the NES version.

Mike from Morgantown

I bought Uncharted twice, because I was an idiot and sold it to a friend, then later thought, "You know, that was a kick-a$$ game, and I'd like to play it again". Though I did buy it used for 20 bucks at Blockbuster...

Sure, with Age of Empires II (and the complete set). I also bought several VC games, even though (or maybe because of) I already or previously owned the game.

Neverwinter Nights (lost disk)
Buldar's Gate (lost disk)
CoDWaW Wii - Once for my son, then for a friend, then when my son moved in with his mom had to get another copy so I could play with him.
Wii Sports (stolen)

I will be very narrow in my interpretation. I am not going to talk about replacing a broken game, or buying a game I previously owned, but had gotten rid of at some previous point. Nor will I talk about a game I got incidentally via another purchase. Removing those I have actually bought a game to have more then one copy of said game.

It was a massive title, and by buying the second game I was able to create a second account on a server. I actually bought three copies of this game, and gave one to a friend. So yes I have actually intended to buy more then one copy of a game.

Oblivion : I have the PC and the PS3 version ( got the PC first but somehow I prefered the PS3 controls and playing from the couch).

Diablo 2 : I have 2xD2 and 2x D2expansion....


Star Wars galaxy : I have 3 copies ( the game was 1 character/account and I wanted 3 characters...).

I've bought Super Mario 64 3 times (the original, the DS remake and the VC version).