Oh man, the memories! Well I think everyone can agree your first NDK is always an amazing experience just because it's the first and everything is so new. Like someone else mentioned, the first year NDK moved to the Mariott was my first year having a room and staying for the whole weekend, and it was great to have a room to relax in as well as stay for the full weekend for once.
I also love going into the atrium and looking at the wall scrolls and various items hanging from the balconies. It's just kinda fun, like personal fan decoration to the hotel for the convention, it's great to see what stuff goes up throughout the weekend.
Last year was my first year wearing a costume. Wasn't a particular anime character, instead I was my own created Ninja Monkey Master. Lots of fun, simple costume but I decorated a stuffed monkey so he was a ninja monkey and carried him around. It was my first time being glomped, and asking for my picture taken. It definitely was cool, and made me realize how much fun cosplaying is. Though my stuffed ninja monkey got more attention and hugs than I did...kinda jealous...but I'll be dressing up again this year as the Ninja Monkey Master, I'm so happy!