Velocity Vector
If you're going to play games on the PS2, you need memory cards to save your games and settings. They're widely available and not terribly expensive, so don't let yourself run low on space. Always keep an extra PlayStation 2 memory card or two on hand--you're going to need them sooner or later, and they may not be available cheaply once the PlayStation 3 comes out and PS2 sales start to fade.
Don't trust third-party PlayStation 2 memory cards? Then use the official PlayStation 2 memory cards from Sony. They're available individually in black, or as color-coded two-packs:
Don't want to pay a premium price for a PlayStation 2 memory card? Satisfied that third-party memory cards are just as good as the Sony product? Give Nyko brand memory cards for the PlayStation 2 a try: