iZotope Ozone - DSP for enhancing audio. Analog modeled EQ, tube compressors and amplifiers, room simulators and more. A lot more.

Put simply, Ozone makes music sound better. Ozone adds warmth, bass, sparkle and an overall desirable sound to your MP3s. Unlike other "enhancers", it improves your music by modeling the analog characteristics of vintage audio equipment such as tube amplifiers and valve equalizers. So instead of sounding harsh and hollow, your music sounds deep and full. The free version allows you to select from presets that simply make music sound better. The full version gives you control over a EQ, bass compressor, tube amplifier, and room simulator settings as well as a preset system that's simply unmatched.

This is a very slick plug-in that allows you to add that extra flavor to your audio files. The interface is top notch and engaging...complete with some very handy configuration settings, this is sure to help you get the most out of your song files. The free version has a great many options disabled tho, so you'll probably want the full version to get the good stuff.