site
The site I picked is www.space.com.
It is a very “busy” site, but manages look professional while doing so. The graphics are clean and high-quality. The layout of the site is such that the important stuff is center left and your eye immediately goes to it. The rest is arranged around it with the site navigation on the top and rest down the right and below. While there are ads, they are related to the sight and not obtrusive in any way. It includes streaming video and images but none take over the page as soon as you visit, you have to click to get them.