Good question!

I think it should be a balance between good looking and the contents. As you said, there are so many stuff presenting a lot of ideas, products... I'm sure you always stop in that ones which have a good look...

If we don't give our presentations  a good looking, no body will stop to read it! But in fact, it's important to deliver a good content if we want people to come back to see what we are producting or, perhaps, sell it to them!!

Very good question!

In my opinion it depends on the audience and the topic. If you are speaking infront of specialists you may use more content based präsentation but if you are speaking to an non technical audience you should try to make your technical topic more "interesting" by using lets say "design elements".

I agree with Martin - it really depends on the audience and the topic. As a soft-skills trainer working with undergraduate and graduate engineering students, I try to remind them how important it is to tailor their presentations to their audience and the environment in which they are presenting. Personally, I prefer a 'less is more' approach to slide design in general. I notice that when my students return from internships, many of them tend towards creating presentation slides which are very text-laden and packed with detailed visuals to underscore the technical content because they have seen this style used in companies. However, the presentations sometimes suffer as a result, as there is simply too much information on the slides for even an expert audience to follow. As always, the art is in striking a good balance!