Re: SD memory card.
^ (this was for Khumar B not for you Baba :) ) Sony doesn't use SD cards.
There are so many brands, there shouldn't be any preference either. I go by size and price higher and lower respectively.
#let uz chat#: No there are no compatibility issues only issue you may face would be size coz some camera support uptil certain size like you may not be able to use 4 or 8 GB in some cameras. I have SanDisk SD cards in camera and in my Treo.