Although Microsoft still doesn't seem to be backing Silverlight with all its heart, mind and corporate effort (see Silverlight out of the MIX spotlight) the beta of Sivlerlight 5 is now available to download as announced on Day 2 of MIX. 

New capabilities include Hardware Video Decode, for enhanced video quality and performance, and “Trickplay,” which provides variable-rate video playback with audio pitch correction. It also has new support for remote controls, multicolumn flowing text, PostScript printing, 64 bit OS support, a better XAML parser and reduced network latency.

A major change it the introduction of an XNA-based interface for delivering 3D visualizations within applications. The graphics are GPU accelerated and there is a facility "immediate mode" that lets you work directly with the GPU. This brings Silverlight up with the 3D capabilities of HTML5 via WebGL. 

Just in case you thought the Microsoft had forgotten about HTML5 for a moment it is worth pointing out that the press release about Silverlight ends with:

"At MIX, the U.S. Navy Blue Angels demonstrated a dynamic new site that uses HTML5 to make the site’s core content engaging and wide-reaching while using Silverlight for streaming a never-before-seen, HD video experience from inside the cockpit and a high-performance, interactive, 3-D representation of a Blue Angels aircraft."

Well at least we had a few paragraphs without mention of HTML5.

A download of the beta is available at http://www.microsoft.com/silverlight

Further reading

Silverlight out of the MIX spotlight

Silverlight is dead, long live Silverlight?

WPF & Silverlight at risk from Microsoft's passion for HTML5

Silverlight better than HTML5?