Idea originally from here (http://brainstorm.ubuntu.com/idea/3028/), and already has nearly 700 votes on it.

"When you are extracting an archive in File Roller you get a progress bar with a little box that moves to the left and to the write. The problem is that this gives no indication of how long the file will take to uncompress. I know that in Windows there is a progress bar the moves depending on how much of the file has been uncompressed. You can also check this manually by comparing the size of the uncompressing file to the total size that it should be once completed."

Comments about this can be found in the above link.