Depends on budget and music taste. My room is that size and I have the Model One's and have been very, very happy. With really solid stands and the right matching gear, the Model One's will sound very good and will give you very surprising bass.
Model One's are very fussy about matching gear, I have had Linn, Creek, Classe, Forte, YBA..etc but the best I found for my set-up is the Ayre AX-7e integrated. I am more than pleased with these two together.
I've had the Mani's and they are awesome and can blow you away with it's bass, they are the big brothers of the Model One's but I would think you need a bigger room and matching them is even harder than the Model One's. It's not a cheap set-up in any way to get the most out of them.
Have not heard the forrest but I believe the newer Totem models are more forgiving in matching up gear. Compared to the orig. Mani's & Model One designs that need serious high quality juice to make them sing.
I'm always out listening to lot's of new gear but still can't imagine getting rid of my Model One's & Ayre AX-7e. I am very happy with this set-up.
