I'm not exactly sure why people have like 5 memory cards. I only have 3 games in my posession at the all times. Currently it is:
Gran Turismo 3 A-Spec
Grand Theft Auto: San Andreas
Burnout 3: Takedown
I just take back what I don't play, like a 3 for one deal, that' s what I will be doing with GT4 at EB Games, I'll get rid of those three above, as long as I complete Grand Theft Auto: San Andreas. I'm a very SLOW gamer, I usually don't try and rush to beat a game.
For example IGN claims Burnout 3: Takedown single player will take 30 hours to beat, it took me 60 hours.
They claimed San Andreas would take 60 hours, but I am at 34% and have played 45:23 hours. If I chug along at my pace I will beat the game at about 136 hours.
And of course 3 games on your mem card isn't going to fill it.