With stuff like hardware, K8V SE, P4P800 SE, 9200SE, 9600SE, 9800SE etc it stands for Special Edition but in the case of videocards, really it should stand for stupid-edition bcause often you lose some features.
Watch it. The 9600SE for example stands for a downclocked and cheaper memory 9600 Radeon. Have a search on google, and see the performance differences between the two. This definitely does not stand for SPECIAL, but rather SLOW ).