Umeda is a futuristic part of the CBD and has many of the city's best hotels and top-end shops. It is also in the north of town and is well connected by the subway and municipal railway. Umeda buzzes day and night with white-collar types and tourists and also has some top landmarks, like the Umeda Sky Building.
This smart area of town is typified by large department stores and shopping malls, but is eclectic, with reams of boutiques and wine bars. Midosuji is right in downtown Osaka and has highlights like the Dotombori Bridge. There is also a decent theater scene nearby and you can go on a sightseeing cruise along Osaka's canals.
Kyobashi district is northeast of town and is a decent mix of new and old. It is best known for the huge Osaka Castle, the large Osaka Business Park and the many waterways in the area, making for good walking and a nice atmosphere.
Nanko is one of the newer, up and coming areas of Osaka that lies in the south of the city. It fronts Osaka Harbor and the bay and is one of the best areas to eat seafood. One of the star attractions is the Osaka Aquarium, while sea breezes cool the area in the summer.