I liked all the worlds the game had to offer. Each one was very detailed and had something special. Particular worlds that I grew acustomed to would have to be Twilight Town, Hollow Bastion, and The World that Never Was. Twilight I enjoyed very much, as it was a very detailed world and offered many sites of interest. You really got a feel for the town setting, and there was factories, trams, trains, and plenty of buildings. It was definitely a big place, as you could look off at the Train Station and see a vast sight of tons of plaes. Really cool in my opinion.
Hollow Bastion was really neat too, as it was also a vast place (check out the view by the shops), even though it was small. Main reason I liked it was because it was my home "base" in between doing missions and visiting worlds. I always used that as main saving spot when finished for the day, as well refueling my guys with items after completing a world. And, it had most of the FF characters, which is a nice plus in my book.
I had been wanting to see The World that Never Was ever since the hidde video on KH. At the time, I thought that town would be the Twilight Town we heard about but of course I ended up wrong. The town looked so cool, dark, and mysterious in the video, I just couldn't wait to see it. When I ended up there finally, it was a "Oh!" moment, as I realized this was the very place we saw in KH.