<p>I am a Winforms and business engine developer who is using asp.net for the first time in over 2 years, and in that time I have noticed a few convention changes.</p>

<p>What is the logic behind the anti-'tables for layout' movement?</p>

<p>Is it to allow css classes to be used to handle layout, and if so, should this really be an issue on pages you are fairly sure will remain static, or is it just considered 'ugly'?</p>

There are a number of reasons. One reason is accessibility...layout tables do not add semantics to the content so screen readers have trouble with them. So only use tables for tabular data.
Here
are a few points that answer the question in more details
Tables are slow
Tables can be inflexible
Accessibility issues are easier with CSS
Tables don’t degrade
Tables don’t print as well