Yheti, I've been playing earth on a 10" netbook with firefox on ubuntu for a while now, and with some minor tweaks it works well.
Get the new firefox 4, it has the menu consolidated into a single "firefox" button, which can sit eg. next to your open tabs. Customize your other toolbar to have one or two buttons, your address bar (which doubles as your search bar) and your hyperlinks all together in one line - alas more browser area for your content.
To further enhance it, look up FF addon Stylish and search some of the boards in here (B&S i think) for threads on adjusting the styles to remove some of the clutter.
This is my screen while playing in non fullscreen mode:
http://img135.imageshack.us/f/earth1f.png/
If you use the F11 full screen in ubuntu, your other programs will still be there, you just have to use alt-tab to get to them. Alternatively you can add another desktop (shortcut could be ctrl+alt+left/right) and put your extra programs on that desktop.
This is my desktop playing in fullscreen - plenty of room for earth.
http://oi51.tinypic.com/2mmbakl.jpg