LED strip and SD card
I had the same problem with using the SD reader with a SPI SRAM. It turns out that the very cheap SD reader cards do not like multiple SPI components on the same port. Since the Arduino has only one SPI, the only thing that worked was to use a SD data logger card.

To add a tristate solution by using two resistors on the MISO line also did not work in my case.

See my post for the post I created regarding this probably similar problem.