The long-awaited PhysX chip has been delayed until 2006. This is down to not many games currently support the technology - though this will all change very soon!
The new Unreal Engine (3) will support the PhysX, and as with previous Engines, many other games will utilise the Unreal Engine 3. The Playstation 3 will also support the technology, giving it yet more of a boost.
What does all this mean to you? Well, if you play games, and require the latest in PC technology to do so, then this is ideal. It'll take a lot of the 'weight' off of your CPU in terms of physics calculations, enabling games to run faster and 'feel' that much better. In reality, it probably wont make such an impact, but I can definately see the benefits. CPU speed is slowing, this along with faster memory access (- see solid state technology) will give the much needed speed boost in tomorrow's games.
The above picture is of the reference boards for the PhysX technology - note the cooler, it's identical to my Thermaltake jobby on my GeForce 4 Ti4200. If it weren't for the green PCB, then, well, I dunno.