Memory cards are now coming in absurdly large sizes. Compact flash cards are available up to 64gb capacity and SD cards come as large as 32gb. Unless you’re doing high-def video, a memory card of that size is total overkill. Instead of getting one large memory card, I suggest multiple smaller cards. Don’t bring one 8gb SD card with you on vacation – instead bring either 2 4gb card or 4 2gb cards. The more the merrier. Imagine taking 1000 images during your once-in-a-lifetime Italy vacation and losing or damaging your 8gb card? Doesn’t sound like a good time to me.
When purchasing a new memory card, keep your eyes open for the read/write speed of the memory card itself. Many of the cheaper memory cards are 15 or 20x read/write speed. A memory card of that speed will greatly increase the time between taking photos on a digital camera – a VERY common complaint amongst consumers. Make sure you get a card that’s at least 60x speed. Again, with this one, the more the merrier. Faster cards = more money, but it’s worth the price.