Very few pieces of media currently support 1080 progressive scan display. For reference, Apple recently announced that it would release new movie trailers in 1080p format, provided gamers used their new Quicktime application. Additionally, a couple of movies (namely Terminator 2) support 1080p.
While a lot of televisions do not currently support the ultra high-end format, it's great to see Sony looking way into the future for its next system.
UPDATE: We have just been updated by our away team at the SCEA conference that not only will 1080p be supported by the system, but that this is considered the standard resolution for the system. Every game for the PS3 will be in incredible, indelible, indubitable HD.
Nobody at IGN even owns a TV that can do 1080p, but that's the system's goal - to give HDTV a killer app piece of hardware that people will no longer be able to live without. Get your wallet ready...