I have a love–hate relationship with Beamer. On the one hand, it gives you all the typesetting and scripting power of TeX on the projector. On the other, it's taken the whole idea behind LaTeX—nice clean documents by default that you don't have to fuss with—and skewed it into monstrosities like this: bad typography, gaudy clip-art bullets, and a nauseating IKEA color scheme. The navigation tools at bottom only add to the noise (does anyone even use those?). It's effectively the worst of both worlds—you have the difficulty of slogging through TeX code, but end up with the amateurish design of PowerPoint anyway.
Unfortunately, all the default themes are like this (there are some nice third-party schemes, such as this one). I took some cues from Jean-Luc Doumont, removing information not directly relevant to the slide itself, eschewing bullets except for actual lists, and minimizing clutter while still framing the slides’ content. (I also used a respectable font.) The result is (I hope!) clean without being boring.
footline includes a color bar on the bottom to match the header bar.