After grad school, I worked in the ticket office... got to know the hall pretty well, sat in every section.
These are just some things I remember... your mileage may vary... and this is info from a number of years ago, but I doubt too much has changed...
Best places (in my opinion) to sit were the Dress Circle (front of lower balcony) , the Gallery, and the Terrace. The very ends of the Dress Circle can be really fun places to sit; amazing vantage point. The one on the opposite side of the low brass section side was always one of my favorite places to sit. The Lower Balcony tends to be the most sought after seats, as that's generally considered the place that sounds the best overall. I wasn't that crazy about the back of the Lower Balcony though.
The Upper Balcony can be good too if you get towards the very front. Boxes sound good, but you sorta gotta sit in the front. They are more of a social thing though, not worth the heavy price.
Places on the floor are good, but try to go about 1/2 way back, not too far back though. Sides are not too bad as long as you are not too close. The sides are less of a compromise the further back you go.
Places to avoid are the back of the Upper Balcony (some have obscured sight lines due to pillars) and the front of the floor. I would choose the back of the floor over the very front of the floor, and the front of the Upper Balcony over the back of the Lower Balcony.
The Gallery is pretty much always good, yep it's the nosebleeds but it sounds GREAT, and tickets are reasonable.
The Terrace is a lot of fun, as you can literally see the notes on the players’ pages and see every gesture of the conductor. Those seats sound pretty good too, better than you might expect.
It’s a great hall... I used to miss the pre-renovation sound (it had an angrier “crack’ to the sound) but it is still amazing.
Anywhere you sit, the orchestra sounds superb. You’ll get to be in the same space as one of the world’s great orchestras. Treasure those moments! The entire space is a living breathing entity, just like the orchestra itself, enjoy the idiosyncrasies and don’t go to the show hoping it will sound like a recording, it won’t. It’s better.
Protip: the “meaty” rep is often on the second half of the show, right? Well, some of the older folks get up and leave at intermission and don’t stay for the second half, so if you are stealthy and cool and nonchalant, sometimes you can move to a better seat after intermission, as long as you don’t have to stumble over people to get there or take anyone's seats who are coming back.
SuperProTip: Wait until the lights dim to quickly grab the newly vacant seats, as the ushers are less apt to bug you right before the music starts...
SuperDuperProTip: I'd sometimes get there early, as a certain "Northern" player would give his parts a last practice go-thru on stage before the concert started. ...which can rock your socks.
