Dear Nola:
PdEspaña area is downtown, and there will be, in all probablity a fair polica presence. I am not sure exactly where your apartment would be located, so I cannot say for sure. I would generally say that Madrid has much less crime (except for the usual assorted pickpockets and purse-snatchers), especially violent crime, than just about any other comparable US city. Everyone roams around all night, partying, and I think the downtown area would be hopping until at least 3 or 4am, hence many people around, plus there is good taxi service (the Metro closes, depending on the station and season around midnight, unfortunately).
Of course I am a fairly burly man (read overweight and tall!), and have more intimidation factor in my favor! If I can remember, I will ask some of my friends about the area, but it would help if you could give me the name of the barrio or general area, if not the exact location.
Generally women are pretty much mobile all hours here, but usually in groups.
Good luck, and consider other towns nearby for apartments. It is less expensive, less noisy and gets you closer to the Spanish people.
Best in Spain,
Martín Shellabarger
MadridMan: Sorry for the esignature ad in the other reply! We met a couple of years ago at your fiesta across from Atocha. I was with José Duende. . . When are you returning?