I like the idea of vector shapes, all the talk can have a standard radius, and i would sugest selecting the points of two sides of the rectangle, shown in red, to resize (while holding shift if need be. Because I made the little tag off the bubbles as a seperate entity, I can dictate where the speach is comming from to suit my needs. a simple white fill layer shape with an outline. Don't worry the thin grey lines won't show when you click on the background layer. having them so easy to move means that if i wanted to type using photoshop, a text layer would appear above this one, i can change either the text bounds or text bubble to suit.