I use that tripadviser website. People take pics of what the hotel actually looks like and post up reviews. The pics the hotel takes makes almost every place look nice, but if there's cockroaches snorting coke off dead women, you might not wanna stay there.
I usually establish a price range, and try to get the most for my money within that range. I've had good luck with Omni hotels as far as nicest hotels for the money, but some of theirs cost a grip.