Well, personally I grew up with the classics, but as time passes on I started seeing the spin-offs.
GX I wasn't too keen on, but 5Ds really took a lot out of me, considering the huge character development as well as the atmosphere of the story itself. Zexal is growing upon me, so you can say that every one of the series truly holds a piece in my memory.
Season Zero...I wanted to replay that show so many times. Although it was the only one never aired in America, it was also the only one that showed many different shadow games as well as having the first story of how they met told in so many ways.emotion_kirakira
Now if they only start getting a little more serious on the romance...sweatdrop
I guess I'd have to say I liked 5Ds the most. I hated that no one needed tributes for monsters in Duel Monsters, and I watched the first couple of eps. of Zexal and I couldn't stand the main character... I liked the E-heroes a lot, so GX came close. I don't like turbo dueling in the games, but Synchro summoning has made dueling a lot easier for me, and I love using Naturia monsters! Of course, I always have a E-hero and a Neos deck ready!
I love season 0 and Duel Monsters the most. The spin-offs don't really do it for me. I think the ancient Egypt focus is what really pulled me in in the first place, and without Yugi, it doesn't feel like Yugioh, you know?
Growing up around the origional DM series that's probably the one i'd go for, but i'd also never say no to the abridged series and season 0 (trying to watch this series in japanese but reading more of the manga to get other parts that i can't find). i'm kinda warming up to Zexal, but i don't watch it very often, the other spin offs i wasn't a big fan of either though..
Season 0: I saw a few episodes of season 0, and I'm not done watching it, but it's pretty interesting so far.
Duel Monsters: IS THE s**t! I grew up with Yugioh Duel Monsters and it will forever be my favorite!
GX: I was excited about it and I watched it, but it became boring as I kept watching. To me the only arc that i liked was that whole society of light season and also the only thing I liked about GX was that it took place in a school for dueling and that the students are in a dorm based on their dueling skills. I thought that concept was actually pretty cool.
5Ds: The whole card games on motorcycles idea was dumb, and I thought the whole show would be stupid, but 5Ds is not that bad, it's pretty interesting.
Zexal: I hate the main character! nuff said.