Was looking through the hotels listed on
www.ratestogo.com and
www.wotif.com, and what's good for you depends on which location you are looking for and what facilities you require, but overall these doesn't seem too bad:
(1) Robertson Quay, Furama City Centre and River View: If you enjoy clubbing or night life, these three hotels are in good locations for the clubbing strip along Mohd Sultan Road, Clarke Quay and Zouk. Furama is right next for the Clarke Quay and Chinatown train stations for easy access.
(2) If you are willing to pay a bit more, try the Royal Plaza on Scotts, which is along Orchard Road and offers a complimentary mini bar. Meritus Negara is also recommended as it is run by the people who also run the Meritus Mandarin, the grand dame along Orchard Road. The Negara would also be quieter as it is not along the main streets, but on one of the side roads.
Finally, once you made your decision, I would actually recommend calling the hotel reservations directly or check out the websites. 3rd party websites don't always give the best deals. Doesn't harm to call to get a better deal.