WireTracks
WireTracks is a company that was formed in 2002 to provide methods for adding hiding wire in existing buildings.
Their first product, WireTrack Original, is a "behind-the-baseboard" wire channel. To install the product, you cut out the sheetrock behind the baseboard, install the channel directly against the framing, and attach the cover to a standard piece of baseboard molding. The integrated baseboard/cover assembly can be removed to allow future wiring upgrades.
Their second product, WireTracks NC, is designed for new construction and functions the same way. The only difference is a shelf that provides precise spacing and allows it to be installed before the sheetrock.
Their third product, WireTracks CM, provides the same functionality for crown molding. However, it offers the advantage of not having to cut out sheetrock or navigate around doorframes.