Recently I've been trying out some of the new HTML5/CSS methods.
However, I've noticed that not all of the most popular browsers have implemented the latest technologies.
Applying some of the new styles may keep your web page up to date, but be careful and check that your new page works on every browser.
One of the most frequently used objects on your page will be buttons, the obvious way to navigate around your site.
Creating a smart and eye pleasing button, or a whole row of buttons for navigation adds to the whole look of the theme you've decided on for your web page.
A lot of people use their mobile devices for casual browsing of the internet, so using the new techniques instead of using images can be the difference between fast download times and a impatient user redirecting and trying another site.
The same goes with using page or menu gradients without the use for images to achieve the same effect.
So, if your building your own site, check your CSS against as many browsers as possible or you could be publishing content that isn't being seen the way you intended.
Martin BlueFlux Graphic Design A Simple Web Page Using HTML5 & CSS3