I think removing all layout related markup from any web page (except for the DIV and SPAN tags, which also serve to mark logical blocks as well as provide hooks for style sheets) is always a good idea. While many browsers do not handle the fanciest features of CSS well or consistently, uncoupled style makes it more likely that your page will render well in browsers other than Netscape and IE. It also allows users the option in those browsers to easily override your styles.

IIRC, the stats pages are already well done, and the move to CSS should be smooth.

Personally, I have no objection to cookies as long as I can choose to not accept them and still get to all of the information.