I just found out my projector can only use 1080i... I know most broadcasts are 1080i but arent some 720p only. Which ones? Is HD worth it if I can only do 1080i
Whatever device you use to feed your projector (HD receiver, DVD player, Xbox 360) should let you select whatever output format you want and convert the incoming signal for you.
720p is used by ESPN, ABC, Fox and some local stations.