In addition to standard speech recognition and transcription into various applications like Word and Pages, Dictate also allows you to control your Mac by voice including support for Automator and AppleScript. According to our man on the show floor, it's impressive enough that it has won a Best of Show award.
MacSpeech Dictate will be available on February 15 for Intel Macs starting at $199, and registered users of iListen will be able to crossgrade for $99 unless purchased in 2008, in which case it will be $29 (iListen has been discontinued).
Update: A press release has been issued with more specifics on pricing. The crossgrade price for iListen users is actually $99; the $29 crossgrade is only available until April 15 to people who purchased iListen in 2008.