With Windows 7, there are easier and faster ways to rename multiple files in one sweep. The first way is to click on a file's name and rename it as usual, then press the "Tab" key to access the next file in the list.
Another way is to select multiple files (press the Ctrl key or Shift key and select the desired files), then right click on the first file and choose "Rename" to give it a new name. The rest of the files will be renamed with the same name. For example, if you name the first file "image", it will become "image (1)" followed by "image (2)" and so on.