We were lucky enough to have a nightingale singing in the garden for a single day recently. Sadly, it looks like it was just passing through, but I did manage to get a decent long recording of it's wonderful song, so here's a tiny snippet!
http://www.goldswift.co.uk/sound/nightingale sample mono 8000.wav
or:
http://www.goldswift.co.uk/sound/nightingale sample mono 8000.mp3
Sorry, the links got chopped up, to save cutting and pasting I've converted it to this:
http://tinyurl.com/fg25k