Since April 2000, Inc. has enlisted entrepreneurs to rate Web sites in various categories for its Best of the Web feature. Gathered here are their top picks. Most of these Web sites were rated "A" sites. (In May 2001, the letter-grade system was dropped. Now judges are asked to pick their top site.)Because the Web is such a volatile business environment, it's hard to keep up with all the sites -- even top-rated ones -- that have gone out of business. We've omitted ones that we know are defunct. If we steer you wrong, please let us know.