Charlie Borland was desperate. He e-blasted all of his photo friends for help. During an important assignment, he dropped a filled CF card on to the ground. In that common-finger-fumbling-careless nano second, the card became unreadable.
What to do? Charlie eventually paid a recovery company big bucks to pry open the card to recover the data.
Not to sound pompous, but card fallibility motivates me to use minimum sized cards. I use 2 and 4 GB cards for 12 megapixel cameras (D3 and D300s) and 4 GB cards for 24 megapixel (D3X) equipment.
My thinking: if for some reason one of the cards becomes unreadable, 2GB of information (for a 12megapixel camera) causes me to cuss less than say losing 16GB of files. Plus, the cataloguing system I use works perfectly with the number of images I can pile onto a 2GB card (with a 12 megapixel camera).
Ah, but can't the additional times you mechanically replace filled smaller cards with a new one cause wear and tear or even bend a pin. Yes. But the Nikon cameras I use (D3, D3X, D300s) have two slots (which i can configure in a number of ways). In the very unlikely event that one slot becomes unusable, there is the other. Thank you Nikon.
So for me, size matters. Smaller is beautiful.