Interesting question, but I doubt broadband internet cracks the top 10 best investment in a home when it comes to ROI! Most homes purchase decisions are based on schools, kitchen, bathrooms, size, and location of the home. If broadband internet was the ONLY decision criteria, we would all be lined up to move to Mountain View where Google is offering FREE wifi.
Will someone pay $4,000 more for your home than your next door neighbor who does NOT have broadband!? We doubt it.