Fukuoka is a cool little city, with lots to offer everyone.
I've come back a few times, enjoying it more every time.
It is right on the ocean, and has a great beach area. An interesting downtown area, with parks, great shopping, and canals/waterways running throughout the city. Mountains surround the city, so adventure awaits those who like to get away from the hustle and bustle.
It's very easy to get around on bike, and shopping/eating is much cheaper than other cities in Japan or Korea.
I'm a sucker for a nice beach....
The main beach in Fukuoka is easy to get to by bus or bike.
Take bus to the tower, and it's a 3 minute walk away.
There are a couple restaurants selling burgers, ice cream, and drinks at reasonable prices.