PC Magazines' annual editor's choices have been announced for 2004 - 100 Top Websites You Didn't Know You Couldn't Live Without.
New this year, PC Magazine also analyzed other aspects of the chosen sites, such as Popularity (determined by Google backlinks), Loading Speed, and OS and Server Software. (Side note: more of the top 100 sites ran on non-windows platforms than on windows, and over half ran on Linux.)
They also created a downloadable favorites installer containing all the links in all the categories. Download the file, follow the setup instructions, and you're all set.