Bolindilly,
Typing control-c in the Terminal doesn't quit the Terminal, it just quits the process that you're currently running in the Terminal (it quits most things, not all though). So if you've got top running and you control-c, top will quit and you'll have your command prompt back. You can also suspent (is that the correct term?) the currently running program by typing control-z, this will bring the prompt back without quitting the program you had going. Then type fg to get back to the program you were running. Of course, as someone else recommended, you can have multiple Terminal windows open, so you can leave one up just for displaying top.