Rockit Pro DJ is one of those examples, because it integrates into the same program everything that a professional DJ can need to perform his/her work comfortably, and under a totally editable graphical environment. The application is capable of playing audio files (MP3 or WAV) from four different sources, as well as videos or image galleries. It is compatible with the majority of MIDI controllers of the market and with multichannel audio interfaces.
It offers you all kinds of controls over each track (pitch control and pitch bend, cue loops and 3 band EQ with kill function per channel), it allows you to view the waveform of each track so you can accomplish a perfect synchronization of each mixed song and it has a sampler from which you can launch your own loops or effects.
If you're looking for a workstation to mix music, that is totally customizable and that is easy to handle, Rockit Pro DJ is one of the best options available.