I build all my freesites 740 px wide and I don' intend to change that anytime soon. They're guaranteed to fit in an 800 window and still look quite good (in my not-so-humble opinion
) on my 19-inch monitor at 1280 x 1024 resolution. I review at that resolution also. I'm not a side scroll nazi, but if there is one at my setup it has to be pretty huge.