I just got a pair of 6.5" in-ceiling speakers from Monoprice price.

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0542.jpg

My living room is 17'9" x 18' and I want to mount the speaker toward the back of room. However, I don't know how to determine the placement before cutting holes. I took some pics of the living room to give you a better idea of what I'm working with(excuse the mess).

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0527.jpg

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0528.jpg

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0535.jpg

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0536.jpg

Here are some pics of the front of the room.

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0532.jpg

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0533.jpg

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0530.jpg

http://i179.photobucket.com/albums/w303/ctl46/Home%20AV%20setup/IMG_0530.jpg

I appreciate any suggestions.