A logo gives identity to a site. A prominent button graphic makes an important link stand out. Avoid excessive or superfluous graphics. Avoid making graphics for titles or links when plain text will do just fine. Studies show that Web users tend to ignore graphics, looking at text first.
Search engines can have trouble listing content from sites that use frames.
It can be difficult or impossible to print a page in a frameset. Frames make a page incomprehensible to some screen-readers for the blind. Here are a few sites that exemplify good information design to one degree or another. Not all these sites are perfect, but each has many of the qualities that make a good Website. The New York Times presents a ton of information clearly and logically.