Before I too jump on the application bandwagon ;) -- what can sysops do that mortals can't?
Just a few "dangerous" functions that we don't want to give to the general public: permanently deleting articles and history from the database; querying the database in SQL; moving articles to a new name with history (we'll probably make that one more available after a bit more testing and debugging); blocking the IP address of vandals.
wikipedia-l@lists.wikimedia.org