This is brilliant! Something new gained... I've used booking.com just recently and no problems there - searched most of the others mentioned, but didn't know about hotelscomparison, makes life much easier. Anyways, there's always priceline.com, wotif.com and hotwire.com - although the latter mostly works for US only. I've used priceline a good few times always with excellent results! There is also travelsupermarket.com, also works for flights (but better i guess is skyscanner.com, although that's only for flights)