My most-important-to-me "piece" of memorabilia is a memory of an experience, not a physical object.
Gotta go into the Wayback Machine... (Long story, btw)
It starts with my having watched Jason Kidd play in-person MANY times at his high school (St. Joe's, Alameda, CA), including his very first game as a freshman. For that game, a few people going in had heard about this freshman who was supposed to be fantastic, but the real draw was Calvin Byrd, a 6'5" All-American senior who had signed with Villanova. He was the subject of all the talk as we went in... Jason was ALL the talk leaving the game!
I saw some 70 Jason games in person over the next 4 seasons, the last two of which tiny St. Joe's won the Division 1 State Championship. During that time, I had talked to him a little bit here and there, but not much...
So he went on to Cal-Berzerkeley, where he starred for two seasons before he entered the NBA Draft, where he was grabbed by Dallas.
That December, I moved to Portland, and happened to see that Dallas was coming to play the Blazers in just a couple of weeks. I went to Ticketmaster and luckily landed a ticket on the baseline, just four rows up.
So, I decided to do what the autograph seekers do, showing up at the back entrance WAY early. While waiting for the door to open, a bunch of kids with programs, pens, etc. showed up... They looked at me (age 37 at the time, and without anything to sign), and one asked, "What are YOU doing here, old man?".
I told the gang that I had watched Jason play tons of times at his high school and just wanted to say hi to him, congratulate for making the League, etc.
Of course, the kids didn't believe me, laughed in my face... I insisted, said I'd even talked to him a little...
One of the kids asked, "Okay, you think he'll know you?"
I answered, "Maybe, maybe not. It's been a couple years and he's met a lot of people since I talked to him."
This back and forth went on until the doors opened... Everyone rushed to the corner of the floor where the players leave the locker room, and I joined them.
Eventually, the players started coming out, Jason being the obvious center of the autograph hounds, all reaching out and trying to get J's attention and sign their goodies. Jason shuffled along, signing without saying much, hardly looking at what he was signing.
Finally Jason got to where I was. I just stuck my hand out for a shake, and said, "Hey, how you liking the bigtime!?"
Jason saw my hand, heard my voice... He looked up, and with a look of surprise, blurted out, "Hey! What are YOU doing here?"
I told him I had just moved, ran across a ticket, and came to see him play... We exchanged some small talk for like 2 or 3 minutes before he said, Okay, I gotta go get ready," and jogged to the bench.
Okay, that was the set-up, now HERE is the memory!
I turned and started back into the main arena... and there were all these kids with eyes VERY vide and obvious shock on their faces!
I think one said something to the effect of "Man! You REALLY know Jason Kidd!! OMG!!"
I could have pushed the front kid lightly in the chest and watched 'em all fall like bowling pins (I didn't).
Anyway, to me that sort of memory beats ANY autograph or pic...