I rely on LiveReload (http://livereload.com/) for my day-to-day web dev work. Point it at a repo folder and a browser window, and any time any files are changed in the repo it'll intelligently update the browser window (full page refresh for HTML/JS changes, partial refresh for CSS-only changes). It can also be configured to auto-compile SASS/LESS/CoffeeScript/etc, and/or execute arbitrary shell commands on save. The Mac version costs $10 (haven't tried the Windows port yet), but it's unbelievably fantastic.