The Westin Chosun hotel at Haeundae is also a good choice. It is the hotel of choice when US Presidents visit Busan. The park right next to it is a great walk. Novotel hotel is nearby, approximately in the middle of Haeundae beach. Novotel will be a bit closer to Haeundae subway station. If arriving at Busan train station, you can get to either the Westin or Novotel by subway (approx 1 hr, need to transfer at Seomyeon), bus (line 1003, approx 40 minutes, no transfer), or taxi.
Seomyeon is also a popular area. Place can get a bit crazy at night, but otherwise, it seems like just like many other urban areas in Korea.
The Park Hyatt has a fantastic afternoon tea set. Went there late once and was able to watch the city come alive as the sun went down. Great view from up there. Also the Starbucks located at Gwangalli beach has a very nice view of the beach from the second floor. Not a bad place to have coffee.