MB, GB, TB!

Jeez, how long has it been since I have paid attention to this? Storage for personal computers has gone off the deep end. Today I saw an ad for a portable hard drive that connects via USB. This drive is 1 terabyte of space! My god, that's HUGE! I know what with video file, photo files, MP3s, people need a lot of room but 1TB! How long before petabytes start popping up?!?