FinderMinder resizes Finder windows when they are opened. There is a small delay before windows are resized and you have to keep it running on the background though.

I use this script to reset the properties of windows manually:
tell application "Finder"
if number of windows is 0 then return
tell Finder window 1
set toolbar visible to false
set sidebar width to 0
set statusbar visible to false
set current view to column view
set bounds to {474, 250, 1318, 750}
tell its column view options
set shows icon to false
end tell
end tell
end tell
When you move or resize a window, Finder saves its dimensions to a .DS_Store file. You can make all folders use the default dimensions by deleting .DS_Store files:
sudo find / -name .DS_Store -delete && killall Finder
It also removes Spotlight comments, resets the positions of icons in icon view, and removes folder-specific sorting modes and view options.