This opt-in beta is available immediately to all Steam users. If users already have Steam installed on their computer, they can take part in the beta by clicking this link and then selecting "UI Update" under Beta Participation. If they don't have Steam installed, they can download it here. To preview the new Steam client without taking part in the beta, a complete rundown of the new features is available here.

Increasingly the most effective way of reaching new gamers is through the existing players of a game. With the new Steam release, gamers will now be able to see which games their friends have purchased directly within the Steam storefront. 25 million gamers create a highly effective and knowledgeable source of purchase suggestions.

With users purchasing more and more games through Steam, new methods of library management were needed. The new client introduces library customization tools to help gamers sort, group, and find games in libraries which for some hardcore players contain hundreds of titles. In addition to having lots of games, gamers needed methods of tracking all of their achievements in a standardized cross-game fashion, which is now possible with the new release.

"We made hundreds of changes to the Steam client as a result of customer feedback on the interface, performance, and functionality," said John Cook, Director of Steam Development at Valve. "For example, we swapped out the Internet Explorer rendering engine with WebKit, which gives us a bunch of size, stability and performance benefits. This release of Steam leaves us well prepared for another year of strong growth."

Major features:

Complete overhaul of Steam client UI design to improve discoverability of features and to better expose all the information related to games in your library
Complete overhaul of in-game overlay UI design to create a richer in-game experience exposing context sensitive information related to the game you are currently playing
New game details view, presenting a detailed view of all the information for a single game in your library
New grid view, presenting a graphical view of your game library
New news page in the store/client/overlay which aggregates from Valve related news sites, official community groups, and third-party gaming news feeds
New downloads view in the client, making it easier to track your progress downloading new games or game updates
New Steam store design, including more integrated community features, improved recommendations, and improved video and screenshots viewing (and much more!)

Store details:

New Steam store/community integration — see what your friends have been buying and playing as you browse the store
Improved store layout, genre navigation, and genre pages, including more robust navigation per category
Improved game detail pages, including quick link to demos, inline display of higher resolution game trailers, improved screenshot browser, and improved game recommendations
New game-specific video page, containing all of a game's trailers in one place, now in higher resolution Flash format
Improved discoverability of sales and discounts, including prominent shortcuts and consistent store-wide visual presentation for price cuts
New quick-info tooltips on store home page and genre pages which allow users to read about games before navigating to detail pages
New search filtering options- search for packs or DLC, easier to use filters for searching by price and metascore, and sort by release date

Client feature details:

View of your most recently achieved achievements and likely next achievements in the client game details view and in the in-game overlay
View of friends currently playing a game as well as all friends who sometimes play a game in the per-game details view
View of related game news in the client game details view and in the in-game overlay
Clock in the in-game overlay (!)
User customizable categories assignable per-game, by which the various game library views can now be filtered
Tracking of last played time for games to show in the client library views
Sort your games by last date played
Library list view displays larger graphic, and a new column displaying a game's Steam Cloud state
New invites section in the friends list UI allowing you to accept or decline invites directly without going to your community control panel
Cloud support for many non-machine specific local settings such as favorite servers
Implemented new DirectWrite based font rendering for the client and in-game overlay on Windows 7 or Vista with both SP2 and the "Platform Update" installed. This offers improved pairwise kerning for text layout as well as better anti-aliasing of text on supported platforms.
Display of total played time in the client game details view and the in-game overlay
Type to jump support in the games list, grid, and game details views
Better Steam cloud conflict resolution support, with the ability for users to choose how to resolve conflicts between machines
Improved forward/backward navigation in the client UI, acting across various different view types (e.g., games list, to community, back to games list)
New style and layout system for Steam's VGUI UI toolkit, enabling much more complicated flowing layouts. Skins will need major overhauls to be compatible with the new client, but will also have much more power and flexibility available to them via the new .style and .layout files used in the new VGUI code.
Backup/restore wizard
Community: all official game avatars in one place, linked from your edit profile page
New outer glow effect supported when rendering text in VGUI
Support for alpha blending of gradients and text in VGUI
Support for many new layout and placement commands in VGUI
Support for native drop shadow effect on primary Steam windows on Vista and Windows 7

Bug fixes:

Improved reliability of auto-login to store and community when used in the Steam client
Improved truncation of long text strings in many places
Fixed the various UI states and settings to persist across client restart more reliably
Fixed being unable to reliably delete previously added non-Steam shortcuts from your games list
Fixed forward/backwards navigation on Community tab getting stuck on redirects
Many small performance and memory usage improvements
Improved sorting consistency between views
Fixed hit areas on friend panel down-arrow affordances to make clicking on them more reliable
You can now remove a blocked friend without having to unblock the friend first

General improvements:

Now using a WebKit based rendering engine for the client and in-game overlay web browsing components (replacing Internet Explorer)
Improved speed of in-game overlay web browser
Improved search functionality on the Steam news page
Web pages which use confirm() or alert() calls in javascript no longer break the in-game overlay web browser