sd vs sdhc memory card

what is the difference for a casual, recreactional user of these two cards? How is speed a difference for this camera?

I agree with Brenda on this. Any memory card can fail or become corrupted. And when you're on vacation the last thing you want is to lose the opportunity to take pictures until you can recover that media card with a software utility. If your card goes bad, swapping another one for it at that moment is of advantage so you can keep taking pics. Then, later when you're in front of your PC, you can use a utility like "F-Recovery" to get back your pictures and recover your card.
No need to lose the moment because you relied on one card one when several can solve that problem. At the very least, you want to get more than one of whatever size you settle on.

One last thing. Cards have different speeds. The faster a card is, the quicker it'll save the photo and cycle to be ready for another shot. In the end, your camera is only going to be as fast as it's slowest link in the chain. So check for speed when you purchase a card.

Thanks to you both! Never considered that I might encounter a problem with the card. I like the idea of several 2GB cards but might get one 4GB SDHC to try for the speed. Thanks so much.

Well just because a card is 4GB doesn't mean it's faster than a 2GB. There are classes. Rated to 6. The higher the number, the faster the card. But you won't find many SDHC cards below 4, IIRC, or SD cards above say, 5.

I'm learning every day!! I'll look for those numbers as well. Thanks