Sam, when we go to Gothenburg in business and stay over night we live at the Gothia Towers Hotel. They have a restaurant at the top that I like. Check out
www.gothiatowers.com . It takes 5-10 minutes with a cab from Radisson Scandinavia.
I´ll ask my friends in Gothenburg what else they recommend and get back to you.
Welcome to Sweden, land of the midnight sun !