Firefox/Chrome: Small netbook screens make you really appreciate every last pixel on your device. The Mini Wide userscript for Gmail adds a "netbook mode" shortcut to Gmail that removes navigation and ads for a streamlined, netbook-friendly, message-focused view of your inbox.
(Click the image above for a closer look.)
Once installed, just tap 'w' to toggle between the default Gmail view and netbook mode. That's all there is to it. Assuming you've mastered Gmail's keyboard shortcuts, the lack of navigation isn't all that big of a deal — plus you can easily bring back the default view with a quick press of the 'w' key. The tweak is a little rough around the edges at times (I couldn't use 'g' + 'l' label navigation unless I toggled out of mini mode, for example), but it's a nice start, and could be really useful for netbook users.