IDI, KAR, WAV, WMA, AC3, OGG, MPA, MP2, AU, AIF, SND, etc., and video formats VCD, MPEG, AVI, WMV, ASF, OGM, DIVX, DAT, SVCD, etc.
You can sing your favorite song and record it to high quality WAV file, so you can listen to your voices after having sung your own free version. Then, you can keep them in your HD or delete them, it depends on you.