If it's possible, sure the savings will be well worth it for the SE/Rs, but don't fret if all you can afford are the standard models - they are excellent.
Your room dimensions should give you plenty of space to allow the speakes to image very well. You'll want to pay attention to placement of your subwoofer as well as your seating position as your room is very close to a square. In addition, the ceiling height is a close factor to the width of the room. If your subwoofer placement options are limited, then you may want to play with its phase a bit or even consider saving up for another sub.
Again, just follow our setup tips and you should be in pretty good shape.
The 66-SE surrounds are very cool - and disarmingly large.
