Oh, I stumbled across a great post this morning while having my morning Mountain Dew. ( I don't drink coffee when its hot outside. Its hot in Mississippi.) Anyway, there are some great plugins on this list from Smashing Share even I have never heard of.
OperaView
OperaView is an Addon/ Extension for Mozilla Firefox and Flock which is very similar (and actually based on) IE View.
Even if you are using Mozilla browser all the time, sometimes you need to view the page you are looking at in Opera browser (especially if you are a web developer). OperaView makes that process easier by adding the item View This Page in Opera to the page context menu, the item Open Link Target in Opera to the link context menu and a button to the toolbar. If you want to open a page in Opera quickly, just right click somewhere on the page and choose new menu item.
MeasureIt
MeasureIt is a Useful Firefox Addon for Web Designers. This Addon draw out a ruler to get the pixel width and height of any elements on a webpage.
Window Resizer
Window Resizer resize your browser to various standard resolution sizes. It is useful for testing different screen sizes. It accurately resizes your browser so you can test to see what a web page looks like in all of the standard resolution sizes. Supports the 640×480, 800×600, 1024×768, 1280×800, 1280×1024, 1600×1200 resolutions.
If you develop, then you firefox. Check it out.
