I don’t really have one best moment. The entire year was great. At the end of 2015 (October) I came back into collecting Pokémon cards and started my Pikachu collection. At the start of 2016 I probably had less than 250 Pikachus, but now I have 696 with 14 more incoming.
The entire search for new cards to buy for my collection, discovering new Pikachu cards you didn’t knew existed (even last week), and adding some absolute gems to my collection are all great moments for me. Some memorable moments were finishing my Pikachu Jumbo collection; the arrival of my first Art Academy Pikachu card; the arrival of the last regular Base Pikachu card (Korean unl. ed.); winning some auctions: like the two Mitsuhiro Arita autographed Pikachus, or the 175/XY-P Event Organizer Stamped Pikachu that I won today. All in all a great year for my collection.
But, the best part of this year was being part of this awesome community! Chatting with all of you; seeing new posts; enjoying pictures of all your collections; hear your stories; the Secret Santa event. Everything and everyone here on the E4 forum is what made 2016 an awesome year. Here’s to many more to follow! 
Greetings,
Kevin