I've made some progress, though tables are still alright for the data that makes more sense in a tabular format, like a list of orders or the shopping cart. You wouldn't want to use DIVs
everywhere because there are so many other tags that make more sense for certain things, depending on the situation, but I know what you're saying. We don't need tables for product displays, options, forms, etc., and .Net gets in the way too much of the time.
CSS is already used for the majority of presentation except for certain places where .Net defaults are in place and sucking up the joint, or the developers got lazy. OK, a lot, actually.
I've come pretty close with
www.passengersonly.com so far, without spending a crazy amount of time on making everything 100% semantic, but focusing the time I have on flexibility instead. The categories, for examples, are unordered lists instead of tables, and I've fixed most of the validation issues. Still requires a lot of work if I want get OCD about it, though, and on top of that a lot of the changes that would still need to be made are in the code-behind and core, which isn't my area of expertise (if I had one).