I agree with Tom. Store the original: let the frontend uppercase themselves if they want it that way. If they decide to force the transforms back down to you, you won't have spoiled your input. If they are querying on that column, a functional index on lower(col) would be nice. To answer your original question, yes, let the front end deal with the problem, leaving you time to worry about more traditional database-related problems. :)
Cheers,
Greg