Libertad street is near to my house but I wouldn't recommend it. Although I don't think it's unsafe, it's a very narrow street "hiddend" among many others. I'd suggest main streets.

Note also that most buildings in the city centre are quite old and so they are the apartments!.

Regards,

Antonio
_________________________
The best tips from your favourite hostal in Madrid.
Hostal Chelo at http://www.chelo.com