I like to stick with a name brand. I've used Lexar, Sandisk and PNY memory cards and never experienced any problems. There are other brand names such as Delkin, Panasonic, Transend.
We have quite a bit on information about Memory Cards in the Accessories section of the site:
http://www.digicamhelp.com/accessories/memory-cards/If you have other questions, please let us know.