There are other good CompactFlash card manufacturers out there, but I seem to end up with mostly SanDisk cards. SanDisk cards are among the highest quality available - and the Extreme III series is built to hold up to extreme professional use. These cards offer the speed and reliability needed by professionals and desired by all.
The gives me the capacity I need to shoot as much as I want without running out of memory. Of course I pay for that later when I need to select the keepers. Though not the fastest available cards right now, the Extreme III cards are very fast - and quite economical compared to the current speed leaders. A fast card saves time during the image upload procedure as well.
If you don't need 16GB of capacity, there are many lower-capacity models available.
FWIW, SanDisk Corporation owns the "CompactFash" trademark.