I think that Mat's medallion is one of the more important things he has received.  And though it hasn't really got any votes, the Horn is amazingly useful.  

 

I think the medallion is one of the more useful in that it protects him from weaves, and helped him fight the gholam.  And it lets him spank Aes Sedai.

 

The Horn is incredibly useful; I mean, it allows him to bring all of those heroes back to help fight, which is pretty awesome.

I think the problem I have with the medallion is that I think it should have been more useful - here's something that protects you from Channelers, and all he's done with it is spank an AS.  That's not to say I can think of anything else to do, but...  it's still disappointing.

 

I guess technically anyone could have blown the horn, but since Mat did I'm including it in the list.

I say his memories are the most important. Also the medallion let him fight the that one thing I'm forgetting the name of.

gholam? :)

 

I'd say that to date allowing him to fight the gholam is the most important thing the medallion's done so far.

Incidentally, for those who picked the memories...

 

tDR (before Rhuidean!)

 

   "Fascinating," Verin said. "That the Old Blood could flow so strongly in anyone today." She and Serafelle put their heads together, talking softly, but with many gestures.

 

...

 

   "What was that he was shouting, Mother?" Elayne asked, then hastily added, "If I may ask."
   "He was ordering soldiers." The Amyrlin gave the young man lying on the table a quizzical look. He had not moved since collapsing, but Egwene thought his breathing seemed easier, the rise and fall of his chest more rhythmic. "In a battle two thousand years gone, I would say. The Old Blood comes again."
   "It was not all about a battle," Nynaeve said. "I heard him say Aes Sedai. That was no battle. Mother," she added belatedly.
   For a moment the Amyrlin seemed to consider, perhaps what to say, perhaps whether to say anything. "For a time," she said finally, "I believe the past and the present were one. He was there, and he was here, and he knew who we were. He commanded us to release him." She paused again." 'I am a free man, Aes Sedai. I am no Aes Sedai meat.' That is what he said."
   Leane sniffed loudly, and some of the other Aes Sedai muttered angrily under their breath.
   "But, Mother," Egwene said, "he could not have meant it as it sounds. Manetheren was allied with Tar Valon."
   "Manetheren was an ally, child," the Amyrlin told her, "but who can know the heart of a man? Not even he himself, I suspect. A man is the easiest animal to put on a leash, and the hardest to keep leashed. Even when he chooses it himself."

 

Mat had some memories of battles even before Rhuidean, almost certainly not enough to measure up to the memories he gained in Rhuidean, but still...  SOmething to think about perhaps.

I'd say it is a tie between his medalion, which allows him -and later others- protection from channelers, and also his ashandari, which allowed he, Thom and Moraine to escape the tower of foxes and snakes.

But as of Towers, the medallion hasn't protected anybody from the Power.

 

Somehow it got caught up in Elaynes mess in Caemlyn with the DF but I can't quite remember how

 

And it was her imperfect copies that saved the day there, not the actual medallion, although tbf the copies wouldn't exist without the original