1. A drug to cure HIV-AIDS.
Finding the right protein: >$1bn. Determining what protein is the active ingredient in a given liquid using mass-spectrography <$5m.
2. Inventing the Office 2007 Ribbon.
Cost to make: >$50m
Cost to implement, given a working implementation: <$10k
3. Inventing Windows XP
Cost to make >$1bn
Cost to invent Reactos - a copy of Windows XP made by copying Windows XP, < $10m.
Innovative companies that do things differently lead the markets
That, right there, is proof that patents work.