Another option if you're flying through on Singapore Airlines is to book a Singapore stopover with them, the pricing is pretty good, especially if you're looking for the other benefits included in it as well - take a look at
http://www.singaporeair.com/saa/app/...entSite=global .
Otherwise I've found pretty good pricing for rooms at
http://www.asiarooms.com/singapore/singapore.html - I've used them before and had no problems. I'll actually be staying in Singapore over the Christmas break too, and this time I used Priceline, got the Le Meridien for SG107+taxes. But regardless I'm sure you'll find somewhere decent to fit your budget too!