I have come to find that I am a demanding user of SD cards. I create DSLR videos that chew up Class 10 SD cards and spit them out. The one that remains is the SanDisk Extreme Pro.
One of the main reasons I use SD cards are for my two Canon 60D's. These DSLR's will not tolerate the standard Class 10 SD cards. Through trial and error I have determined that every time I shoot video I have to wipe my SD Card and Format it. I have also found that the SanDisk Extreme Pro is the best way to go. I chose the 16 GB card to force me to swap cards and improve my system of redundancy, but some people opt to for the 32 GB.
Now for still images I can get away with basic class 10 SD cards, but if you are shooting bursts of mulltiple pics a second I would recommend the Extreme Pro. The main reason is that I shoot in RAW format and this chews up my buffer speed and relies on a quick write speed of the SD card. All in all it is hard to find a flaw with these beauties and I am happy with their reliable performance.
What about you? Do you have a favorite product or device that you can't do without? Let us know in the comments below.