Your One Bullet Point Solution; Electrical Upgrade

Two points; I am well aware of many threads on topic of electrical service. I do not have time to read hundreds of posts, but wish to distill them down with your help. I will also post this on the Tech Forum to get wider response:

Doing service upgrade to 100A. I plan on adding a whole house surge protector, type 2, add on to panel after the service enters house. Panel to the HT/Music room is not under consideration, as it was all updated when the room was built.

If anyone has important info/contradictory info on that plan, please inform.

What I would like to know in shorthand form from the community from those who have Done upgrades:

1. Recommended Panel? Brand, any difference?

2. I currently have sub-panel for HT/Audio room which I’m tempted to keep. I understand that this is a good move.
Electrician can sum all into a larger panel, but I have reservations. Comments/recommendations?

3. Particular wiring/breakers for panel/sub-panel for audio use?

4. Particular surge protector recommend.

As the topic has been covered much, notation form comments are welcome. Thanks for helping!

I would assume you are doing this undertaking to make sure that power is not a limiting factor in sound quality.  Before you spend all these money, lets look at what and why.  Given that otherwise power quality is acceptable (no EMI, etc.), the main limiting factor from AC power would be too high of output impedance, i.e. sagging even for a shortest time under changing load.  A valid concern, since this introduces nonlinearity, intermodulation distortion, and reduction of dynamic range.  But the current rating of your incoming power and details of your distribution panel are not the main bottleneck in the entire power budget.  The in-wall wiring and all the old twist-on connections are.  Unless you recently upgraded your wiring and know exactly what it is, my guess is that likely you have AWG12 solid wire connection at best, or even thinner wire.  NEMA requires AWG14 for 15A branches and AWG12 for 20A branches  With long runs and likely several twist-on connections with possible oxidized copper you may not see much actual difference once you are done with the upgrade you've mentioned.    
If the situation with wiring is what I described, you would better off using a good quality power conditioner that would compensate for the deficiencies of old wiring.  To toot my own horn, my company makes EMI filters for industrial applications with very low output impedance that compensates for some problems in wiring, as well it gets rid of EMI just about completely:
However many slots you put in, you will want more! I like Siemens. I have a small sub panel for my lab, a middle sub panel for kitchen, HT, and music room, and a very large main panel. I still have a few slots left over.

Never lost a Siemens breaker in 20 years.
Doug, don’t forget a meter socket SPD. This is the first line of defense in terms of surge protection. Depending of where you live, you might have to ask the power company to install it for you and they will charge you a small monthly fee. It goes outside, right behind the meter. Most people miss that part. Good luck. N.B. The equipment and its maintenance is handled strictly by the power company.

I have worked with most circuit breakers over the years starting with my Dad 55 years ago.  He told me back in the day that Square D would never let anyone down.  I can add Siemens as another.  When adding new panels for audio make sure to specify annealed HC copper busbar materials, not brass or Cuponal.  Square D (Schneider Electric) and Siemens both supply them.  Be sure to treat the busbars with a copper preservative to slow down oxidation.  This is especially important in humid climates.  A very good one is Thomas and Betts CP8-TB containing colloidal copper.
Some important details I do not know- Is this a smaller townhouse
with gas heat, stove, water heater and no a/c needs?

I may not be following your goal here.

A new panel under 200 amps is considered an oddity
in the markets I have lived in. Unless you fit the parameters I stated
earlier and have very limited a/c power needs.

Normal procedure when installing an service upgrade is
to eliminate sub panels. Have you run your thoughts by
a good electrician yet?
You have some of the plan down. Run 2 dedicated 20 amp circuits
to your component location. 12 gauge wire is fine.
No j-boxes along the way.
One circuit for audio and one for video.
Use the same bar in the panel for both new lines and do not put it
on the same bar with a/c or refrigerator.
Buy better grade receptacles for inside the home.
Offer at least 4 plugs-ins per 20 amp circuit.

Consider this whole house protection Surge/Filtration/Waveform Correction item-Environmental Potentials EP-2050

Grounding is very important. A 10' 1/2" solid copper rod is $13 at Home Despot.
Ask your electrician to test the existing one to see how effective it is. 

One thing not in your control:
-Distance to the nearest transformer? 

Things that screw up sound reproduction:
Noisy florescent lights, rheostatically controlled fixtures.
Noisy HVAC systems, Noisy refrigerators.

You probably knew all this but clarity counts.

Good luck with the new service!