I don’t want to lose these links, and at the same time I think others might be interested in checking them out, if they haven’t already.
First up is Molly Holzschlag’s article on long-term CSS hack management. Basic idea is keep your browser-specific CSS hacks separate from the rest of your CSS. That way you can drop browser support pretty easily when the time comes for such a thing.
This leads to Tantek’s Mid Pass Filter which allows you to present a stylesheet seen only by IE5/Win browsers.
Which leads to the CSS hack reference I use on a daily basis.
Andy Budd has an article on validation and tackles the debate on whether validation is a tool, or a must. I have a bit of a rant on this myself, sitting in the comments of the skidoo base.css stylesheet. My perspective: validation is a tool, not an absolute law. As long as you understand the rules you’re breaking, and the effects of breaking those rules, then it’s perfectly fine.