The Cardas speaker placement has always worked very well for me, but it recommends that the speakers are further from the rear wall than from the side walls. There's a simple formula for calculating the distances at www.cardas.com under one of the sub-headings.
The only drawback I've found is that the speakers end up quite far into the room, which can cause some friction with SWMBO.
The only drawback I've found is that the speakers end up quite far into the room, which can cause some friction with SWMBO.