I noticed today a little timer at the bottom of a co-worker's browser, showing him how long the web page he was browsing took to load. This tool just became a part of my standard toolkit - the Fasterfox extension to Firefox
Strictly speaking, Fasterfox is a "browser accelerator"; that is, it tweaks various browser settings, overrides RFC specs, and can also pre-fetch data for you. But it also has a page timer - and the other features can be turned off, which is how I now have it configured.
Response times are an important part of doing web development, and it's easy to get an erroneous impression of how fast or slow a page is to load. A nice objective measure helps to address this.
