When you select an audio file in the Mac Finder, Snapper immediately appears right beneath the current window, showing you the wave form. 

Play
Hit the space bar or double-click in the wave form to play. Or use auto-play to start playing the moment you select the file. Vari-speed is available too.

Drag, Drop and Convert
In the Snapper wave form you can select a part of the sound file and:
    drag it out, to create a new file.
    drag it to any sequencer or audio editor (new in version 2...)
    turn the selection into an mp3 file. (or ogg, mp4 flac)
    split stereo files into separate .L and .R files or vise versa
    convert to mp4 and attach it to an email in one go.
    export to AIFF, WAV, BWF, mp3, or m4a.

All of them.
Snapper opens over 50 sound file formats. That includes compressed files, split stereo, 192 kHz, 5.1 surround files, red book audio, cds and movies containing audio. It shows loops, markers, timestamps, regions, BWF annotations, even album covers. You name it, Snapper can handle it. For some formats you need to install external components, here's more on that.

Finder
Snapper follows your file selection in the Finder. It shows a wave form as soon as you select an audio file.

Pro Tools, Nuendo, Logic, Cubase, Live
You can drag (selections from) files directly to the cursor of your sequencer or audio editor.

• Much improved integration with Snow Leopard.
• Spot-to-cursor of Nuendo, Cubase, Logic and ProTools
• Drag selections anywhere, into tracks or even iChat.
• Even smaller cpu footprin
• Waveforms that look better and appear and scroll quicker
• Looped playback
• 64 bit file support
• Trim tool, fades and normalizing
• Varispeed playback without pitch shift
• Recent files tab
• Level meters
• and dozens of other features you have asked for

Requirements: OS X 10.5 or later

Home Page - https://www.audioease.com/snapper/