Basically any mem card will do just fine, as long as you take care of it, and don't throw it around like a soccerball.
I have a few friends too, who have had GC mem Cards and they wiped. Mines working just fine.... although it is only a week old....

But my brother has all kinds of Mem Cards for his PS and some of them are almost 5 years old or so and they still work perfectly, mainly because he doesn't leave them lying around.
Also to make sure that you reduce the chance of losing your information, the least ammount of removing of the mem card from the camecube the better. The friction and the constant going in and out of the slot, will wear it down and make is less reliable.