I was just curious and I know there are already a few other people who have asked this question. You don't have to explain why you like them. (Not including the Arcanum)
Wizard City and Aquila: Elik's Edge in the Shopping District because it just is so cool and I would definitely hang out there if it was a real place. It's great for just wondering about things.
Krokotopia: The Map Room because it is pretty cool to look at Krokotopia from what looks like a digital picture.
Marleybone: Big Ben and the Royal Museum because I think that idea of a musuem is pretty cool and fighting at the top of Big Ben is cool (lol, It is really hard to explain these things because they are just cool)
Mooshu: Cave of Solitude is an amazing place. I remember when I first got Wizard101 I tried porting to one of my friends and remembering them being in the Cave of Solitude. I was like, "Woah, I got to go here it looks so cool!" Imagine the water section of it in nature. As a nature lover I would be amazed.
Dragonspyre: The Dragon ride in the Roost is epic! And the final battle is just as cool because you are right next to Dragon Titan!
Grizzleheim and Wintertusk: Everywhere!
Wysteria: The School of Earth (Where Chester Droors is) is a mysterious tunnel that leads to a cool plant-cave.
Celestia: The Floating Land, specifically the platypus tribe, pretty cool. The Floating Land stands out in Celestia and the Spiral; it is one of the only tropical places.
Zafaria: The Baobab Crown and the Stone Town/ Waterfront because the Baobab Crown is like a giant treehouse and the Stone Town/Waterfront are pretty nice architectural designs and the zoo there is pretty nice.
Avalon: The Keep of Ganelon and the Wild because the keep is wonderful and the receiving Sword of Kings is epic along with the the quests there. The two villages of the Wild are really whimsical and cool places to hang around.
Azteca: The Floating Mountains and Alto Alto/Cloudburst Forest beacuse they have really neat landscapes and ideas behind them.
Khrysalis: I haven't been here, but the landscape features are really awesome.
Polaris: Again, I haven't been here, but I think the Borealis Peaks will be my favorite place. I always have wanted to see the northern lights in person.
Well I'm currently a Lvl51 and some of my favorite places are Polaris shipwreck(Housing)because it looks good with the ice and sliding on ice is one of the fun parts in and out of the shipwreck. Maybe Barkingham palace it has challenging bosses and the dialogue is good. Plus those wooden skeleton keys you have to get good loot that is the good part. Finally meeting Docter Jackall several times and fight him for the first time. Hollow Mountain because the boss battle is nice and is even nicer with players since you get more loot. Winter tusk section with frost bone enemies. I like it because they drop equipment with cards such as dispel and sandstorm. Knight's court in Marleybone is pretty and the enemies are cool. This is all for today. Logan DakewraithGrandmaster51
I just liked DragonSpyre alot because that was actually really fun and it didnt even take a week to do! And I also enjoyed Mooshu because I didnt even know I was halfway done when the Jade Oni popped up right in front of my face.
I'm not sure if I can include Pirate worlds since I love that game more than this one (sorry wizard fans ) but my favorite world is definitely Marleybone and Mooshu.
Marleybone: The reason why I love this world is because the night is really pretty, and all the creature look better than the other worlds. I also love this 'cause this is where Bonnie Anne is from (Bonnie is my firstmate)
Mooshu: I'm not really sure why I love this world so much... it's probably because I love Asian culture, but the creatures here doesn't look right for a place like this.