depends on your budget and style ... as mentioned Horizon centre at Ap lei chau has many in the one building at the mid to high end of the pricing arena but some good finds and prices can be found amongst the stores ( just go straight to the 26th floor , grab a coffee at Tree and work your way down - walking stairs is quicker than waiting for the lift ... otherwise stock standard defaults such as Ikea Home - IKEA with a few others here there and everywhere , Pricerite Priceriteå¯¦æƒ â€“ 家居資訊站åŠæ¾³é– €ç¶²ä¸Šå•†åº— , Seahorse WELCOME TO SEAHORSE , Justco AEON Stores (Hong Kong) Co., Limited. , GOD (goods of desire) GOODS OF DESIRE , Sofa Sale Sofasale Hong Kong Online Furniture Retailer - Buy sofa, sofa bed, cheap sofa beds, sofa sets, leather sofas, chaise sofa, sofas for sale, fabric sofas, tables, office chairs, outdoor furniture, lamps, ceiling fans, bean bags, arts. , artura ficus (also at ap lei chau) ArturaFicus , Aluminium Aluminium - Urban Living , OVO OVO , Mark james Marc James Design , etc etc etc ... should be a start , you can also order on line from places like Manks
Scandinavian Modern Design, SOFA, - Manks Limited in Hong Kong , maybe some second hand stuff like 2nd Chance 2ND Chance Co Ltd etc etc ,
a few hours or days on google can save a bit of groundwork 