How to do a cross-browser testing of web application?

view full story

http://askubuntu.com – I was wondering what would be my best option for testing my web app through different browsers in Ubuntu 12.04. I know I've the option for a VM but wanted to try and avoid that if I could, I'm also aware of browsershots but do not like this. I prefer a real bowser so that I can use developer tools i.e. firebug. I'm open to the idea of anything web based or something I can install on my machine ( though I've found wine to cause me problems with performance of my machine) Any suggestions greatly received! (HowTos)