A Complete LEGO reference CD-ROM and/or WWW-based - complete with a database of every set produced. Important information would include:
US set #
European set #
Set name & description
Official catagory
Official sub-catagory
Number of pieces
Instructions included Y/N
Year released in Europe (or N/A)
Year released in US (or N/A)
Year production stopped (discontinued)
Total quantity of the set produced
Suggested Retail price (US)
Scanned instructions for each set
While there's many sites on the internet that are doing a great job in compiling much of this information there is certain information which only LEGO has (e.g. the quantity of each set produced and the year discontinued)