Prewiring Renovations

Hey folks. Its been a while since I joined in. Hope everyone is still chasing the dream (or is that steam?). We have begun renovations. I was wondering if I could get some input about wiring while the walls have been torn down. We are in a three level townhome with the basement as the main entertainment center. I have asked the electrician for two outlets with dedicated lines in the basement and one for the den up top. I would also like to wire for the possibility of installing a Sonos system in the future (I'm sure that has been a hot topic). Basically I'm looking for any advice as to electric wire specs, cable tv specs (I hear Cat 6), fuses and deceent behind the wall speaker cable. I know about Hubell outlets and power conditioners which can go in later but the contractors are pushing hard. Any and all suggestions would be greatly appeciated. Thanks in advance.
If I were you I would consult someone whose business is installing home theaters and the like for a living. You may get some quality answers here, but your situation is unique to you.
My only observation is to istall more than just two lines.I got 6 lines in my listening room,but I would suggest to go for 4 lines and preferably 20A.Therefore your electrecian should use 12/2 Romex.I read about cryo treated wire and even heavier gauge like 10 or even 8 but in my opinion 12/2 Romex is fine and as per code.In regards to Cat6 I actually installed that in my walls too,but I don't know anything about Sonos .Don'r forget to install Roxul fire & sound insulation in your interior walls before you close them,it makes a big difference.Ceilings too if you want.