I like square ones for wall hangings that are small because usually the pattern is even. Most blocks are square- I say even though I've been known to have some blocks that were squar-ish.
But for beds I like rectangle, even for my queen bed. I like it to drape over the pillows and the foot.
Hmmm.. I don't think I want to discuss body size! I have too much body and not enough size! :)