EZkeys Classic Electrics : Good, but could be developed & polished further

This software allows you to create piano/keyboard background accompaniment to your songs. You tell it what chords to play, and then feed it midi files (your own or from the Toontrack library). It then uses the style of the midi file to play your chord structures. I'm not sure it does it particularly intelligently, but for the most part it seems to do a decent job.

Don't expect it to be quite as flexible as ezDrummer with regard to parameters and editing the instruments. Also the included libraries (and add-on libraries) are much smaller than ezDrummer's. Don't expect it to help you write chord sequences (beyond providing a circle of fifths for reference). Don't expect it to include melodies, or make it easier to add melodies to the accompaniments, or easy to edit the midi. Finally, if you already play piano quite well, think twice about whether you need this software at all.

If you consider all those points, then you will not be disappointed. As someone who cannot play piano, I like it, and feel it was worth the price to be able to add some quick background keys to my guitar/bass/drums songs. But that's all it does.