Mac:
Amadeus II http://www.hairersoft.com/Amadeus.html ($30)
    has support for searching for silences for splitting up a lp recording
    docs mention cleaning up vinyl
    will record direct to disk, and will encode on the fly (not just to aiff)
Peak LE ($99) http://www.bias-inc.com/products/peak/
    i can't get to use builtin mic
    will do recording direct to aiff, up to maximum amount of time
    forcuses on editing and effects
    see also Deck LE.5 ($99) http://www.bias-inc.com/products/deck/ 
        more oriented around mixing
GarageBand http://www.apple.com/ilife/garageband/ ($50 for all of iLife)
    records, sequences, mixes (somewhat), has effects, loops, synthesis
    works with many hardware accessories
    not as oriented around editing, but music creation as a sequencer
iTunes http://www.apple.com/itunes/ (free)
    will rip from audio cd.
    instructions for mp3 encoding from audio cd, aiff, or wav: http://www.wellesley.edu/Computing/Binders/IT/itunes.html
    instructions for convert as import instead of 2 steps (option-advanced in file select): http://www.macosxhints.com/article.php?story=2003060416104210
Logic Pro http://www.apple.com/logic/ ($999)
    acquired from Emagic
iTunes LAME Encoder http://blacktree.com/apps/iTunes-LAME/ (free)
    improved mp3 encoding for iTunes
Audion http://www.panic.com/audion/ ($30)
    records, plays, encodes. no editing.
    has a feature to do batch encoding of CDs
Sound Studio http://www.felttip.com/products/soundstudio/ ($50)
    does audio-level based stopping (can break to a new file though?)
    records to disk
    does mic or line in
Cacophony http://www.bannister.org/software/cacophony.htm (shareware, $25; uses LGPL SoX library)
    supports line-in and mic
    does audio play through
    no record direct to disk. so needs 10MB RAM per minute at 44k
    automatic gap detection?
    focuses on editing
    does 8 tracks
Spark XL, Spark LE, Spark ME (free, but now gone?)  http://www.tcelectronic.com/SparkXL

Windows:
Pro Tools http://www.digidesign.com/ptfree/ (free edition with no plugins for windows or mac 9; no free macos X; part of Avid; )
    DigiDesign was acquired by Avid
    market leader, but not particularly easy to use 
    lots of supported hardware, such as http://www.digidesign.com/products/mbox/
Syntrillium Cool Edit Pro is now Adobe Audition http://www.adobe.com/special/products/audition/syntrillium.html ($299)
    works with Radio Shack "Red Rover" usb controller
    has a "pop/click" tool 
    you can find earlier versions of CEP on the net (from when it was shareware)
Quartz Studio Free http://www.digitalsoundplanet.com/SoftwareHouse/Products/Quartz_Studio/Studio_Free/studio_free.phtml
    see comparison at http://www.digitalsoundplanet.com/SoftwareHouse/Products/Quartz_Studio/Studio_Pro_DSP/Comparison_chart/comparison_chart.phtml
Sound Forge http://mediasoftware.sonypictures.com/products/soundforgefamily.asp ($400)
   has a "Vinyl Restoration" tool
   Vegas Video also does audio
Wavelab http://www.steinberg.net/en/products/audio_editing/wavelab/index.php?sid=0 ($250 euro)
    also Cubase
GoldWave http://www.goldwave.com/ ($45, only an audio editor; MULTISEQUENCE $55 is a mixer)
CakeWalk Home Studio 2 ($199, many other products too)
SoundEdit Pro http://www.rmbsoft.com/sep.asp $39
    don't confuse with Mac OS9 SoundEdit 16 http://www.macromedia.com/software/sound/
Wave Corrector http://www.wavecor.co.uk/
  $45 specifically for tape/lp transfers
CDex http://cdexos.sourceforge.net/
  free, targetted particularly at extracting and converting from audio cd

For lossless audio compression, see:
   http://mp3.radified.com/lossless.htm
   MAC http://monkeysaudio.com/
   FLAC http://flac.sourceforge.net/

Unix:
Paranoia http://www.xiph.org/paranoia/ (free; specifically for audio CD ripping)
GramoFile http://panic.et.tudelft.nl/~costar/gramofile/ (GPL linux; specifically for recording records)
Sweep http://www.metadecks.org/software/sweep/ GPL (favored featured is "scrubbing")
Audacity http://audacity.sourceforge.net/ (windows, mac, linux. audio editor and multi-track recorder.)
   will not rip audio cds
Rosegarden http://www.all-day-breakfast.com/rosegarden/ (focused on midi sequencing, score editing )
Ardour http://ardour.org/ (hard disk recorder, 24 channels; uncertain whether it runs anywhere but linux)
AGNULA http://www.agnula.org/ ( GNU/Linux Audio Distribution) packaging of other software
Snd http://ccrma-www.stanford.edu/software/snd/ artistic license (specifically an editor)
Snack http://www.speech.kth.se/snack/ and WaveSurfer http://www.speech.kth.se/wavesurfer/ (tcl/tk or ruby; theoretically all platforms; Snack bundled with tcl/tk)