Guys xhtml, 4.01 strict is a waste of time, innovate don't regress! Also it's ok to use tables when you are displaying tabular data (a calendar, stock chart, etc.). CSS-driven and standards-based design is about semnatic, relevant markup, not simply ejecting tables.
May I refer you to some important reading material:
Bullet Proof Web Design [simplebits.com]
Web Standards Solutions [simplebits.com]
and important sites: