I’ve been using http://booking.com for a couple years and now find it difficult to book hotels without it. Clean and simple - love the price comparison idea. One suggestion, please make it easier to look for rooms suitable for families and kids.
Usually I stick to the following rules..
1. Decide budget
2. Scan prices from all hotel booking sites (this can be done by aggregators like Hotel Primer Search or Room Rates Direct )
3. Choose the cheapest one and book
I used Booking.com...loved this website because it allows you to book without the commitment of paying (but they do capture your credit card details as a guarantee for no show) and sometimes they even throw in free cancellation if you cancel about a week before. And its always about $1 to $10 cheaper than other sites. I will recommend this besides Agoda.com
you can book from wego singapore, a quick check showed them to give better rates than most other websites. i liked their interface as it is easy to use and loading time is quick too. I booked a few good deals from that website.