unobtrusive speaker system?

Thiel Power Points and Planes.

In Wall, in ceiling

how about the new ZU Cadenzas?

As Tarasound suggests. May be some B&W or Parasound in wall designs. I have B&W in wall speakers all over the house.

Gallo has some small WAF friendly speakers.

orb audio is very similar to the gallo. Might be worth a listen.

Try the Magna Planer Home theater set up,great sound
with planer speakers front and rear plus center. Add Hsu sub for bottom end

I went with the D4 ERA's from Signal Path. Great sound and unbelievable bass from a small speaker. They also come in a smaller and larger version depending on your needs. Check them out at the link below. Good Luck.

http://www.signalpathint.com/index.php?option=com_content&task=blogcategory&id=16&Itemid=36

I have the Gallo A'Diva Ti's and they sound fabulous. They take a little time to work in but once they are worked in they sound fabulous....