[Littleleeroy]

I agree with MeechMunchie's two "objectively justified reasons" for pirating a game but I also pirate a game to try it out before I buy it.
A lot of the time I play the game for 30 minutes and find that I don't like it, so I don't end up paying for it as I won't ever play it again.
On the other hand I remember pirating the full version of Minecraft a long time ago and I really enjoyed it so I bought it, the same with Portal 2; I bought the PS3 and PC version of that.

All the games that I actually play I pay for.

I've torrented most of the games that I own already (like PS1 [and GBC games]) because it's a lot easier than converting the CD to an ISO for playing on the PC or PSP.
As with Job McYossie I've bought AO for the PS twice and for PC, AE for PS twice and PC, MO for XBOX (I actually bought a second hand XBOX just for this game) and PC, and SW for PC and PS3.

I think the bottom line is you can download whatever you like, but if you play it you should pay for it (unless you have already bought it, even for another console.)