Turku is a nice city - I've been there several times. Turku is a right choice for you if you are looking for a city. On the other hand if you wish to visit a small country town then Porvoo could be worth visiting, see http://www.porvoo.fi/index.php?mid=724. Porvoo is only about 50 kms from Helsinki. The distance Helsinki - Turku is nearly 170 kms.