I just came in to recommend installing Web Developer myself; after installing and trying View Source Charts just now I can wholeheartedly recommend it also.
I tend not to use floats for anything except images and tables. For menus and headers, I’ll just explicitly set the thing with position:absolute and left/top/: 0px or more likely 2px.
I approach that kind of web design usually by building a mockup in Photoshop or somesuch, then chopping the bits up and using absolute and percentile positions.
I also satrt off by testing in Firefox, then afterwards do whatever I need to make it look good in IE. Microsoft’s non-standard implementation of margins and padding make this a bit hard, though.
One thing you should do right away - put that orange right border on the “links” container div, not on the links themselves. It’ll stop it looking stepped in FF, and uses the container div better anyway.
forgot to add - set the width of the links container and set the links themselves to width:100%
Also, don’t format the anchor tag like you have there, create a menulink class rather, because otherwise in-page links will look rather silly.