The Philosopher's Toolbox

Working on a revision of the classic Toolbox pages. As it turns out, the hardest thing about moving from a multi-layered table approach to a css-for-visual-formatting approach is deciding whether to go for a transitional design incorporating tables and css for visual formatting, or go with css only. The advantage of the css-only approach is that the pages are lean, clean, easy to maintain, accessible, and can be authored to provide some nice visual layout effects across platforms and (recent) browsers. The disadvantage is that 4.x browsers botch the box model, tables, backgrounds, and other standards so badly that they render the page illegibly, so much so that you have to hide the design from them -- which essentially alienates that segment of your readership. This isn't a problem for me, since only two people read this site and I'm one of them. But let's pretend I was designing for someone with an actual audience. What would I do? A transitional approach which uses tables to lock down structure and set up backgrounds, and uses css for typography and other effects is good, works visually, and makes the design legible to 4.x browsers. But it actually makes the design less accessible to non-visual user agents (i.e. anyone using screen-readers, etc.), and (I think) some non-traditional visual agents (i.e. palm pilots, cell phones, etc). Moreover, you lose the clarity of the page structure (i.e. information structure), the pages become bigger, harder to maintain, and they violate the whole 'separate structure from format' design imperative which I am increasingly a big fan of. What to do, what to do. Do I make life easier for the 4.x browser audience but less accessible to everyone else (including the visually handicapped), or the other way around?