My first concert is a bit tricky. When I was about 10 I saw part of a Tommy James & The Shondells show and then a couple years later stumbled upon a free concert being given by Brownsville Station in a park in Toledo, Ohio.
My first concert as an adult was Peter Frampton at the Toledo Sports Arena. This was shortly after Frampton Comes Alive was released and I believe he played for well over three hours that night. It was magical and in my mind I can still see Frampton on that stage with his long hair flowing as he moved back and forth.
As for my 5 favorite concerts...
#1 Rush at Air Canada Centre, Toronto - September 22, 2007
Myself and 7 friends were able to go through Ticketmaster auctions and get 8 seats in the front row center. At one point in the show we all donned chef's hats (cooking chicken was a theme of that tour) and the look on Geddy Lee's face was priceless.
#2 Peter Frampton - March 30, 1976
#3 Rush at US Airways Center, Phoenix - June 16, 2011
Purchased front row tickets as a gift for my son who had just gotten his PhD from Arizona State. The tour photographer snapped a picture of us (back then you could buy concert photos from him) and I have that photo mounted and on the wall of my office.
#4 Rush at The Ahoy Arena, Rotterdam - October 16, 2007
A colleague and I were in Europe on a business trip and with a free weekend bought tickets to see Rush in Rotterdam as they were recording that show (released as Snakes & Arrows Live). We stood about three feet from the stage for the entire show and I remember these tall, blonde women walking through the crowd with mini kegs of Heineken strapped to their backs. You didn't need to leave your spot to get a beer just wave to the beautiful blonde and she would come your way!
#5 Nightwish at Six Flags Event Center, Des Moines - April 19, 2015
Nightwish play symphonic metal music (think Wagner merged with Metallica) and this venue turned out to be a defunct indoor tennis center. For the VIP meet & greet we were literally standing on the courts in an unused section of the building. The opening acts were okay but my friend and I found our way upstairs to a section that was supposed to be closed. We ended up talking with Nightwish's tour manager for about an hour until he got yelled at and we had to go down to the main floor.