I'm not really an electrician, but it is my understanding if a house is wired/grounded correctly, combined with the built in protection/guts (rectifiers) that most audio equipment has, you really would not need more than a decent surge protection. I think the higher the joules rating the better. Much of my equipment is plugged right into the outlet, and has been that way for 18years, since my first home.

M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85