Roggy,
I was going through some old posts and happened to see this one and I thought to myself, I'll bet he wonders why this was not responded too. Let me try to explain at least in my opinion why this is such a loaded question.
What is bad web design? When you design a site that does not meet the expectations of your audience that is a poorly designed site. The keyword being audience. As a web developer and designer we never truly know the expectations of our audience until the site is online. We can do focus groups, surveys, beta testing, and have all our buddies look through the site design and test it in an online test mode but until it gets online and in front of your audience you will never really know the response to the site.
Anyone on this site, that has been designing websites for awhile, has had a poor site design. Some worse than others. I have had many poorly designed sites over the years. Not intentionally, but based on the users responses, user input, types of traffic, bounce rates, etc, some just did not work out. After developing hundreds of sites that would be expected. It is how you respond to them that separates the professionals from the amateurs.
When we start seeing trends on a new site we study the trends and try to make corrections to the site to adjust to those trends. Most times the site can be saved and resurrected other times we will have to start over. It is all a process. Web site development is so dynamic and based on so many different technologies that you are constantly learning and adjusting to a constantly changing market. That is the reason that most of us love the industry it is constantly changing and we are constantly learning. The things that drive your audience today may have absolutely no bearing on your audience in a year. That is what you will need to keep up with and actually it is quite challenging but very rewarding.
That is one of the reasons sites like WebMasterSun are so popular. The professionals in this industry understand how hard it is to get started and learn the industry and will share most anything they have learned. Most of us that have been around awhile learned most things the hard way. 12 years ago we did not have resources like these or anyone that wanted to share what they knew.
So examples of a bad web design. Look around the web, if you are interested in a product or service and you find it difficult to use a site that claims to offer those products or services, that is a poor web design. We have a saying in development, if it takes more than 3 clicks to get where you need to go on a site, you designed it poorly, rethink the design.
Oh and by the way, if you were thinking about visually poor design, that is a whole new bucket of worm and is totally subjective. Beauty is in the eye of the beholder. There are some sites that I have seen that are just annoying to look at. But you know what, they are very popular. It all depends on your audience.