I’ve been using Firefox for years, but I’m trying out Chromium and so far it’s been great and fast.
You can just go to Ubuntu Software Center and type Chromium to install, or install via Terminal:
sudo apt-get install chromium-browser
If you want to get the latests versions of Chromium add to your Software Sources:
deb http://ppa.launchpad.net/chromium-daily/ppa/ubuntu lucid main
Customize to look like Lucid
You can install the Ambiance theme from Google Chrome Extensions.
To use Lucid system title bar and borders right click on the Chromium bar, next to the tab, and choose the appropriate option.
You can install Google Chrome Extensions in Chromium.