There was a day when only visual design mattered. In many projects today there is the need for audio and video. A great solution for working with audio files is the open source Audacity 2.0. It is a free download and you can get it for Windows, Mac and Linux. Donations are accepted if you want to help keep future development going.
With Audacity you can record live audio and then cut and mix it however you like. It supports most of the popular file formats so you are able to edit almost any sound file you want. For those want to alter the sound, take advantage of the many included effects and add even more via plug-ins. In short, this is a very powerful tool and you can’t beat free!