Normally, I would have done lots of googling before moving to a new country but with Peru, I’m playing catchup. Here are some expat sites from a quick trawl on Google:
I’d say the most “famous” is Living in Peru started by a Dane, Carsten Koch: Living in Peru.
Live In Peru: for finding real estate in Peru. The hot spots are Miraflores, Barranco, and San Isidro, but I’d go for Magdalena La Mar and Lince, if I was looking.
The blog of an expat.
For concerts: http://conciertosperu.com.pe/agenda-conciertos/ (including free ones or “gratis” in Spanish)
And because food is one of the major delights of living in Peru (picarones shown below): Peru Delights