On Mac, use FCP
http://www.apple.com/finalcutpro/

On PC:
Virtual Dub http://www.virtualdub.org/features (free GPL)
Sonic Foundry Vegas ($560, some fanatic fans)
Adobe Premiere http://www.adobe.com/products/premiere/main.html ($699)
Avid Xpress DV http://www.avid.com/products/xpressdv/ ($995)
Pinnacle Video Studio

expensive high end
http://www.discreet.com/products/
Incide Editor E3 http://www.inciteonline.com/incite/default.asp

On Linux/Unix:
veejay.sf.net (oriented around real-time VJ mixing)
Cinelerra
Kino
MJPEG