Tokyo! I started learning japanese about 2 months ago just to prepare myself for a trip to the city! At first I was really intimitaded by the language and for years I thought it would be impossible for me to learn it. Turns out I was totally wrong. You just need the right motivation and you need to learn everyday. At some point it just clicks. Now after just 8 weeks I know each and every character of ひらがな and カタカナ. Kanji are still a huge challenge, but I'm getting there!

Will travel to Tokyo probably in 2020! I'm looking forward to talk with people and really test my skills. Plus japanese culture is just awesome. Even though I'm not that big of an anime or manga person, I still love the games from japan and stuff like Hatsune Miku.

I’ve been to London and Paris, I wouldn’t mind living in both but I lean more towards Paris. Never been to NY and Tokyo but I would love to visit both cities.

You're now too optimistic sadly ^^". Basic Japanese isn't very hard and can just click, true, but more advanced Japanese is simply awful to understand and master... But good luck to you anyway!

OT: I lived 3 years in Paris, and have been living in Tokyo for a year now. Tokyo is in my opinion better to visit. A lot cleaner, people are nicer, and you have more diverse things to see. To live though? Both are bad, smaller cities are way better (not small towns, just smaller cities), the life's comfort is just at an entirely different level. Except if you're very rich, can live downtown comfortably, and enjoy all the city can offer on a daily basis. Otherwise, not worth it. 

Based on my personal preferences I would rank them this way:

Paris >> NY > Tokyo >>> Abyss >>> London

Nah, I know that I will have to learn for at least a decade to become fluent, but that isn't my goal right now. For the next two years, I just want to understand the basics of the language, just so that I can get around in Japan, talk to people, understand them and also understand what's going on in japanese movies and games. From there I will continue to learn the language basically forever.

I handled it in the same way with my english . Once I had the basics figured out, I just started to watch movies and play games in english. In the beginning I had to look up a lot of words, but with time I more and more was able to just understand new words simply out of context. And even if I have trouble to perfectly express myself in english every now and then, I would say my skills in that language are quite respectable by now. 

Well I've been to New York, London and Paris, so I guess I want to visit Tokyo the most?

New York was pretty cool but I spent most of my time in Manhattan.
Paris was pretty good too.
I'm feeling a bit indifferent about London. Certainly wasn't bad, but I have no desire to return.

Out of those I would choose Paris. Weather is definitely better there :)

I've been to Paris and London, so that pretty much leaves NY and Tokio for me to choose from and between those two Tokio wins by a landslide.

I really liked Paris, it's easy to find your way around and public transport isn't the insanity that London public transport is and there's intersting shops to pop into and major landmarks staring you in the face at every corner. It also feels like a big metropolitan city, similar to other major cities in europe like Madrid or Berlin, but it feels relaxed.

London by comparision feels oddly small, like and oversized, overstuffed village. One reason for that might be the english obssession with owning a house, however small it might be. It was always really wierd to me to see this sprawling city, being mostly comprised of tiny 2-3 story buildings instead of the bigger apartment buildings that usually dominate european cities.
It also feels very similar to my home city, despite having about three times as many residents, maybe a bit more antiquated. Public transport rates are outrageous.

While I'm interested in NY, it's more of a 'might be neat to check out' kind of interest (as far as US goes I'm currently more interested in the westcoast although there's probably parts of the eastcoast that are really beautiful.)

Tokio, I've wanted to visit for aaaages. I'm just much more drawn to it cuturally, and the fact that it is clean, safe and everyone is really polite doesn't hurt.

Smaller European cities >>> London > Paris >>>>>>>>>>>>>>>>>>>>>>>>>>> New York > Tokyo

Tokyo > New York > Paris > London

Could we choose more than one? Tokyo, for its cultural background and technology, and Paris, for its museums and gastronomy.