'm sorry but I have to disagree with all of you. I own 2 straight tubes and i wouldn't have it any other way. For one, like someone else mentioned, it's much easier to clean (I've owned both before).
Another reason is that for the most part all of the bongs I've owned and friends of mine have owned, the tubes outlive the beakers by far. I've seen pretty thick beaker bongs break with just a slight tap of a granite counter top or a lighter...