REAPER is a powerful but sensible Windows application that lets you record, arrange, edit, and render multi-track waveform audio.
REAPER provides an extensive set of features, but is a very small and lightweight application (the installer is less than 1 megabyte, and includes many effects and a sample project).
REAPER versions 0.4-0.99 are freeware, but starting with version 1.0 the license will change to very reasonably priced, uncrippled nag-free shareware (supporting full functionality in unregistered form, forever).
* Supports ASIO, Kernel Streaming, WaveOut, and DirectSound for playback and recording
* Reads WAV, OGG, and MP3 files, records WAV files
* Lets you arrange any number of items in any number of tracks
* Supports audio processing plug-ins (DirectX and Jesusonic)
* Volume, pan controls and envelopes per track
* Multi-layer undo/redo support
* User creatable color themes