From Image Line Software:
FL Studio, formerly known as FruityLoops, is a software synthesizer and sequencer that allows you to create drum and other audio loops. This program is easy enough for beginners to learn, but under the hood you'll find powerful tools meant for serious musicians. FL Studio utilizes MIDI and DirectSound (internal mixing), 16-bit 44KHz stereo output, and 32-bit floating-point internal mixing. You'll also get support for VST plug-ins, as well as individual panning, volume, pitch, mix, resonance, and cutoff on each note; digital effects, such as stretching, fading, and reverb; and master/slave MIDI-synchronization capabilities. This version features minor improvements and bug fixes.