The dangling preposition is one of my pet peeves. However, common usage has moved this usage to being commonly accepted. Personally, I try to avoid ending a sentence with a preposition because it can introduce ambiguity. I also hate the dangling it. What is that, you ask? That is when there is no anaphoric or cataphoric reference for the proform it (most people will call the proform a pronoun, but I'm trained in linguistics and we call it a proform). (Anaphoric reference is pointing back to replace the last noun the proform replaces, cataphoric is pointing forward to replace the next noun. Cataphoric reference is a technique used in literature and often not used well.)
PS-get your minds out of the gutter, boys. I know what you were thinking when you read "dangling it."
Not THAT it.