Either Hong Kong or Singapore, I am sure you'll enjoy your stay at either location.
Hong Kong: If you enjoy shopping and I am talking about major scale - "shop and walk till you drop kinda style", I recommend Marco Polo Gateway or Prince located at Harbour City. The hotels are quite affordable, spacious if you were to opt for the suites. One thing good about either hotel is the location. If you wish to cross over and visit Macau for some gaming experience at Sands, the harbour is just a stone's throw away. Shopping at Harbour City is amazing - from upscale French, Italian fashion to local. Watches are plenty and take advantage of the free tax on purchases when you are there.
Singapore: As Andrew mentioned, Ritz Carlton - the one and only 6 star hotel in Singapore. Excellent service, food and spacious suites. If you can get a honeymoon suite, go for it. Pricy yes, but very well worth it and will leave a most impressionable experience for both you happy couple. Location wise, very convenient. Marina Square and Suntec City (largest shopping complex in town) is just within walking distance. Orchard Road - the shopping district is not so near but a 5-10 min cab ride will have you there in good time.