I\'m about to begin working on a web page with a complex table-based layout (coded years ago).
One of the things I\'d like to do is convert the layout to a proper CS
Iterative way works as well. Start with small blocks, converting them to CSS. This should simplify your table structure, hopefully leaving only the "basic grid" in tables and all the rest in CSS.
From there, pick an existing, tested solution if it's a simple layout (for 1 to 3 columns, there are tons of tested solutions out there). If it's more complex, go with Blueprint.