I would like to point out as Eric did several months ago that floats were not intended for layout purposes. But they do function within reason. Also that there are some major problems with the vast majority of how browsers display floats. And there are some big limitations in what floats are capable of doing with layout as I have discussed some time ago.
All of that being said, floats have their place in design and they are very handy for layout purposes. But there are problems with using them, and there are problems with using positioning for layout also. There is no easy solution, but there are options. Remember, use the right tool for the right job. There is no wrong way to design.