Advice for a noob looking at advice about setups and hardware (Sony ddw790)

[llol_slim]

Hi all
I'm afraid another newbie requiring some advice if you dont mind please
This is a (relatively) temporary arrangement, being I will be moving in the not to near future, but for now ..

I am thinking of buying the Sony HT- DDW790 (i was plumping for the 890, but apparantly its being discontinued and the "replacement" ??? DDW800 is out of my price range) - does anybody recommend anything else for around the same money - DDW790 are £140

My setup is currently :
32" cheapish BGM 1080i LCD
PS3

So this is what I am thinking ..
http://img293.imageshack.us/my.php?image=roomwn3.jpg
sorry, couldnt get the image to show!!

My question is, on the image the sandy colour is furniture (bed, wardrobe and tv table) the green aquares are where I imagine I'll put the front speakers and the red/orange are potential areas where I am thinking of the rear speakers.

My question is : Bearing in mind this is a small room roughly 3.5m x 3.5m (i have exact dimensions if it is required) is it ok to mount speakers about 50cm from the ceiling?
That would mean I could use the red squares or if I should use speaker stands that would be the orange squares.

I hope that makes sense!

To clarify my 2 questions are:
1. Do people recommend the DDW790 or is there something better for the same money?
2. Is it ok to mount speakers high up or is there an optimum height?

thanks