Registry handling was improved in this version (1.2.6) for Guest and Limited accounts.

Excellent and useful basic audio edition program especially for users of digital recording devices. Being able to do basic filtering, normalize audio, and cut useless silence is irreplacable. Advanced features for multi-track recording also available. Recommend that users take a few minutes to learn the shortcut keys -- makes the program so much better.

audacity can be made portable by downloading the .ZIP version from here:
http://audacity.sourceforge.net/download/beta_windows

afterwards, unzip the contents and in the directory which houses "audacity.exe" create a folder called "portable settings"

this will write all settings into this folder... hence making it portable.
(instructions are also available here:
http://audacityteam.org/wiki/index.php?title=Portable_Audacity)

use UPX Tool+ to compress "audacity.exe" and you have a portable version that is less than 2 MB.

I am working on large audio material (30min speech - sometimes with music). Functions: Normalize - Compress / Limit, Cut, Equalize. Audacity is much to slow to handle that.
(Wavosaur is better - Nero Wave Eeditor is realy fast, but it is not stable.)

Probably stealth. Delete the registry key after the first time you launch the program and see if it gets recreated

This 'portable' version still creates a registry entry and\or writes to the User folder. If you want TRUE portability, download it from: http://portableapps.com/apps/music_video/audacity_portable