I'd use Priceline if I was looking for "Resort" level hotels. You are looking for a one night stay, so this may not be ideal. +1 for BiddingForTravel.com here.
If I didn't know what off-site hotels were available, I'd use tripadvisor.com to determine the best option. I would make reservations directly from the hotel's web site, unless I was sure I could get a better rate elsewhere. Buying direct means you don't pay additional agent fees, you're not locked into your reservation if you find something better, and you have flexibility on customer service issues. +1 on Entertainment Book here.
Since I do know what hotels are there, I prefer Hampton Inn. Free breakfast, Free WiFi, several in the area, all with decent proximity to the parks. There may be Entertainment Book discounts here as well.
Good luck!