Here are my recommendations:
(not really in any order)
(1) The Oriental - just reopened after a long refurbishment, hence everything is "new"
(2) Pan Pacific - ditto above
(3) Ritz Carlton - for the bathrooms, especially if you're travelling with your loved one!
(4) The Conrad - for the CBD (Central Business District) view (Make sure you request for it when making your reservations)

(1) to (4) are in the Marina area, near the Esplanade (Affectionally known to us Singaporeans as the "Durian" - main concert theatre) and the Merlion (tourism symbol of Singapore). It is not along the main shopping belt, but there are decent shopping malls in the area too (Marina Square - currently undergoing refurbishment, Suntec City Mall, Raffles City, Citilink Mall - underground shopping centre). The closest train station is at City Hall, 10 minutes walk away, through Citilink.

Continuing,
(5) Four Seasons - Oasis in the hustle and bustle of Orchard Road
(6) Goodwood Park - Colonial Style
(7) Meritus Mandarin - right next to the biggest shopping mall in Singapore, right in the heart of Orchard Road

(5) to (7) are in the main shopping area of Orchard Road. The hotels are all minutes' walk from SEVERAL shopping malls (I count at least 8). Besides shopping, it is also close to Newton Food Centre, foodie heaven! Everything is pretty much within walking distance!

Let me know what you are interested in, then I'll be able to tell you more!!