Firefox: ModestTab has a simple mission, one that might resonated with browsers who don't suffer from tab overuse, or those who use fancy tab management add-ons. The add-on simply makes your tabs taller and expands site icons for easier readability.
When would ModestTab make sense? When you've got a very high resolution on a small screen perhaps, or another tab manager installed that makes having double-tall tabs with big favicons less of a restriction than a nice convenience. I've found navigating tabs on my wife's high-resolution MacBook a bit of a squint, for example, so ModestTab might be surreptitiously installed there soon (Actually, I can't, as noted below). No options or keyboard shortcuts, this add-on just does what it sets out to do.
ModestTab is a free download, works
wherever with Firefox 3.0 and higher on Windows only. If you've got a clever add-on combo that makes ModestTab more useful, tell us in the comments.