Just found a really useful feature of IE9. When you close the wrong tab by accident it can be really annoying, however in IE9, when you right click on the tab bar, there is the option to 'reopen closed tab' which will reload the last tab you had. Unofrtunately, it does not remember your page state or anything that you might have filled in on a form (which is probably better for security anyway).

CSS3 is a more mixed affair though. Support for rounded corners works ok, however gradient backgrounds do not work well with CSS3 standards so you have to use the filters that were introduced in IE5. It doesnt support gradients at an angle (only horizontal and vertical) and it does not support multiple colour stops or radial gradients.