Friends of mine stayed at this resort over Chinese New Year and recommend it as family destination. Rooms offered range from a spa room at 2,200NTD to a suite for 24,000NTD. You get to use their gym, foosball, and airhockey sets.
To get an idea where it is (less than an hour from Taipei), check out their map online. Their English site is comprehensive: http://www.southgarden.com.tw/en/html/page-service04.htm