First concert - America
Best concert - That's a tough one. I got to work security will in college so I saw more free shows then I can remember. I remeber my buddy getting hit in the head with a bong at the monsters of rock show.
A couple I liked, The Scorpians and Robert Cray. Another was a few years ago. Pearl Jam and some other artists played a unplugged concert at Benaroya Hall. Pretty cool to see with only 2,500 people there.

Two I wish I had seem - Jimi and Alice & Chains with Lane Staley