Building a new room

Don't worry too much about outlets they can always be changed later. Concentrate on the things that must be installed before the walls are closed in.

Such as, install at least 3 dedicated outlets without any junctions or tie ins. Use at least 10 gauge wire.
You can then install a line for other outlets and a line for overhead or side wall lights.
I also ran cat 7 cable and cable TV and telephone jacks.
If the room may also be used for home theater run the best speaker cable you can afford from the front of the room to the back and sides.

Yes, use insulation inside the walls but don't just butt the 2x4 tight against the concrete walls, leave a gap.

On the ceiling, I used 2 layers of 5/8" drywall, the second layer is glued to the first before final screwing. I wish I had double layered the drywall walls but you may want to.

Milpai,I am using one dedicated line with my PS P10 power conditioner that has just my digital components plugged into it. That also includes video items.

The 2nd dedicated line is for my Pass Labs Amp. And the 3rd is for my 3 JL Audio F-113 subs.
My outlets are all the Furutech GTX Rhodium and the outlet frames/covers are the Oyaide. (I think they look better than the Furutech).

I used some of the sonex insulation in the ceiling , but I also used regular fiberglass in the ceiling and walls. I installed a exterior steel door frame.

The music is muted outside of my room, but the bass still radiates to the upper floors.
I have read that having a separate ceiling that does not touch the ceiling joist are the way to go to eliminate the bass transfer.

On the question of power surge, I installed a whole house power surge protector in the breaker box.