There is no doubt that, with most browsers on a rapid update cycle, there isn't much to say about each release, but Chrome 18 has just rolled out and with it yet more improvements in graphics.
Before we get to the interesting parts, it is worth saying that the new release fixes all of the problems found in the Pwnium competition and a few more. You can find out the gory details at: Chromium security page.
The big news is that 2D graphics acceleration, which was being tested in the beta channel, is not considered safe enough to be introduced to the stable channel. Put simply, if you allow Chrome to update automatically or upgrade manually, then you should notice a big speed improvement in any 2D graphics you view within a web page. The acceleration will only work if the machine you are running chrome under has a GPU fitted. The acceleration also only applies to the Canvas element so games that create their 2D graphics in older ways are not going to feel the benefit.
If you are interested in finding out what GPU support Chrome is actually using simply type in the URL:
WebGL, the 3D graphics environment supported by Canvas, has long benefited from GPU acceleration, but in this latest version of Chrome you might be able to get 3D graphics on older machines that previously didn't have the hardware for the job. SwiftShader is a software based rasterizer that can do the job of a GPU if one isn't available. What this means is that lots of people who couldn't view WebGL graphics, even though they were using Chrome, can now see something - even if it isn't as fast as a real GPU would work.
In addition to the new technologies, Chrome 18 also comes with the latest version of Adobe Flash bundled so you don't have to bother downloading it as a separate task.