Surfing around the internet is fun. What is not fun is waiting for pages to load. Especially for the still large percentage of people who use dial-up. It's frustrating to sit for 5 minutes waiting for a page to load.
Unfortunately bands usually don't realize this. Instead, they want the flashiest and graphically amazing page they can cook up. The most common mistakes are these:
Senseless pictures or movies bouncing around the screen. Takes forever to load on dial-up. Some are lenghty even on speedier methods of internet connection. Even worse than including a flash introduction is not including a "skip" button.
Many bands feel the need to cover the whole screen with pictures so that no white shows on the front page. However, in addition to taking half a year to load, it's visually overwhelming and confusing. It's great if bands want pictures on thier website, just put them on thier own page so that we can choose if we want to take the time to see them. One or two pictures on your main page is good. But don't over do it.
There is a reason MP3s exist. So that you can offer them to fans to download. Please don't force us to listen to your songs by having them load automatically when we come to a page. Even if you are just streaming it, it really slows the rest of the internet down for us.
While not a speed issue, it is very annoying when links are not labeled. Fans have to scoot thier cursor over the screen, hoping to see the pointer hand appear. Then some moving animation will identify the link, which is a loading speed issue.
The front page says it all, "Welcome to our site! Please make sure you have the following plug-ins and fonts installed on your computer to proceed." Regardless of the band, fans should not have to download stuff to make the page work correctly. Especially when the page freezes up the computer when the plug-ins are not downloaded.
Basically, while websites are fun and cool things, band websites are here to service the fan. It doesn't need to be complex and flashy. Just a simple band bio, discography, tour schedule, contact information, and merchendise store will provide a great place for fans to get information. A photo section won't hurt and a link to a message board for the fans is great, also. Just keep it simple and informative.
A great example of this is The Blamed's website. An example of what is bad is the Loudermilk websites and the Norma Jean website.