The image above shows what the US search landscape looks like after recent consolidation. It is based upon a PDF document at Bruceclay.com
There are 10 principal players out of the original 19, however in terms of supplying services and technology (the outbound arrows) there are only 5 companies: Google; Overture and Yahoo with AskJeeves and Looksmart trailing.
1. Google
2. Overture (+ FAST/Alltheweb, Altavista)
3. Yahoo (+Inktomi)
4. AskJeeves (+Teoma)
5. Looksmart
6. MSN
7. AOL (+Netscape, DMOZ)
8. Lycos (+Hotbot)
9. Iwon (+Excite)
10. Go