The Singapore Stopover Holiday programme is usually pretty good value. The thing to keep in mind is that the two days you'll stay are weekend nights though - so many of the top level hotels will have cheaper rates available directly at these times (especially in the holiday season). That being said, given the rates work out about SG$170 per night nett for the C group hotels and you get the transfers and other extras thrown in as well, it's a good package overall and difficult to beat. The Carlton and the Grand Plaza Park Hotel City Hall are both good options as well in the same price range.