I sent an email to you, but we don't have any specific brands we recommend. Customers tend to use what they can find.
The more commonly used brands are Sandiks, ATP, Lexar, Kingston, PNY, et.
SD cards that use SLC flash chips last longer, if you're concerned about longevity.
If you are playing hd video, class 6 or higher SDHC is recommended, for high bitrate video.
We recommend testing the cards to make sure they play your content properly. Not all cards perform up to the rated this. This can even happen with a brand or model that you've used before. Please test before deploying.