(1) Google
The biggest and best of all the search engines and the one that most people use many times a day. It is well known that Google is now used as a verb too, with people talking of googling something or that they googled a particular word. This is the quickest and most comprehensive of the search engines and the one that returns the most accurate results.
(2) Bing
This is the latest offering from Microsoft, and although it seemed to get a reasonable amount of media attention when it launched the penetration has been disappointing. Until the accuracy of the search results gets up there with google then it seems hard to see how this can make any impact on the market.
(3) Yahoo
Yahoo was one of the first major internet success stories. Starting off much more like a directory that then developed into a full blown search engine, this could have been google had it done things differently before the new kid on the block took over and dominated the search market. Now it is something that very few people use daily and the search integration with Bing may be a raising of the white flag.
(4) Altavista
If you have used the internet for long enough, then you may well remember Altavista. This is the search engine that most people used before Google came along at least in the UK, and in the mid to late 90's this was the search engine that was very popular with people. Now it is something that does not really appear to be used much by anyone. It appears to now be part of Yahoo.
(5) Ask Jeeves
Also known as Ask, this service is tailored more towards answering questions than searches specifically. For instance if you want to know what a baby hedgehog is called you might type in 'what is a baby hedgehog called' and hopefully receive the answer.