Before you just go grabbing Google, think again. Google searching leaves a trail that may let advertisers, the government, and who knows who else know where you have been. You can read about Google and privacy by searching GALILEO. You can also enjoy privacy enhanced Google searching with Startpage.com, Qurobe.it, or Duck Duck Go. You can read more about privacy enhanced searching at The Search Engine and Directory Snapshot.
General Meta Sites cover a wide variety of subjects and are mainly for the general public, though they often contain a lot of both newsworthy and scholarly material. Many have live editors that screen out obvious "clunkers" such as term paper mills and quack physicians selling useless nostrums.
DMOZ: Also called the Open Directory Project, Dmoz, uses live editors to add sites to a variety of subject categories. DMOZ includes a Kids and Teens category and endless Regional categories to help those planning trips. The Science and Radio listings are also especially helpful.
About.com: About.com also divides and lists sites by category, often with descriptions and articles written by category editors or Guides. About.com is especially good for recreational and nonacademic topics.
Google Scholar: Google's search engine for the world of scholarly research. This search engine brings up university departments and government and academic research pages, but it also searches publishers' sites for journals' tables of contents and sometimes even suggests books. Note: the journals seen on Google Scholar are seldom full text due to copyright restrictions.
The Internet Public Library: Once a small, well maintained list of sites and pathfinders (combinations of links with descriptions and references to books and journals), on a variety of academic and academicly related subjects. The pages and links can be a bit old, but the librarian/editors were extremely selective. Alas, the Internet Public Library was last revised in 2012. Please watch for dead links.
Science.gov: A gateway to US Federal Government agencies' funded science and technology web pages and also some nongovernment web sites. The site lists government agency pages and online government publications. There are also featured pages. Needless to say, it is advertising free.