i am having trouble setting the preferred application to open files of a particular type.

since installing Tiger all .csv files have a default preference to be opened with *Script Edit* if i do the recommended *view info* (cmd+I) on a highlighted file and select, say Excel under *Open with* the icon at the top of the Info panel is changed to the Excel icon as is the app in the drop down menu.
[...]

Create a new user and see if the problem persists for the new user. If not then you know you need to remove some preference files from the problem users' account.

You could try deleting:
/Users/yourusername/Library/Preferences/com.apple.LaunchServices.plist

Have fun,
Shay
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=========================== Shay  Telfer ================================
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