Having Ubuntu as development environment is great! But, I things get complicated when I came to testing your site on IE. Yes, we can test it using IEs4lin project. But, my experience told me that the result is not quite the same as using IE on pure windows installation.
Yesterday, I got message from colleague at California. He told me about Adobe BrowserLab. A cool service from Adobe to test how our site looks on several web browser. It display the site like Pixel Perfect plugin for FireBug. Give it a try and you’ll be amazed!