It is really up to you. You may use lossless audio codecs like FLAC, or you can record using the same audio codec and the same bit-rate, or you can record using the same audio codec and slightly higher bitrate. Recording 192kbps MP3 streams into 192kbps MP3 seems good enough for me.

Also note that you can try to download/capture streaming music instead of recording it from your sound card.