With the advent of 3.0, I have been adding an arsenal of new web tools to my collection. I'll start the conversation with a Chrome web app.
Tool: Dimension for Chrome for Testing Responsive Design
One of those tools I've found useful lately is Dimension. Dimension is a really nice Google Chrome extension for testing your responsive design without having to resize the browser window. It comes with ruler showing the viewport size, a draggable handle to resize the viewport size, and Preview Mode to simulate the design in various device type.
Have you found any new tools to be especially useful for designing your 3.0 site? please share with us below.