What makes a speaker too big for a given room?

My speakers have side firing woofers. How does this factor into room placement? Does this have any impact on the rules of speaker placement?

I have a question similar to the one posed by Chadnliz. What is the difference in performance between a full range floorstanding speaker and a monitor speaker from the same model line that has the same tweeters and mid range drivers, used with a seperate sub? Is one setup one 'better' than the other. Pros and cons?

Learsfool: Thanks. I was hoping that was the answer.