Memory cards are getting smaller and more data packed worthy. But its also getting so small that its flimsy and prone to damage. Samsung has created a line of cards in metal casing that waterproof, shock proof and magnet proof for this.
The added physical security won't make the cards smaller or slower, but a little bit more expensive though. The SDHC cards are Class 10-rated and come in 8GB, 16GB, and 32GB capacities.