Personally, I've been FatWallet loyalist since 2002, but have found my self expanding beyond FW in order to find some of the lesser known deals. It's funny, because of FW, I've now got everything I need for a house, except the house itself. But now, I enjoy finding deals on items that other people want.
FatWallet and SlickDeals are pretty much tied at the top of the competition. But there are a couple others out there that will soon be giving them a run for their money.
There are two things that really burn me when it comes to hot deals sites. The first is the eBayers (and other auction site folks) who are scouring FW and SD and other sites to find the deals that will make the most money, which usually results in the deal ending too soon for most to even read about it or it results in the killing of a deal (ie. canceling orders). The second is the folks who get in on the deals just to get in on them. Some of these deals are on items that other people need or could really use, and instead the items are bought out by people who will never open, much less use, them. Case in point, a family friend who died last year, and introduced me to FW, had an entire 12-by-12 room packed full of unopened junk, including an unopened Woot box that had 3 Beavers on Cialis.
As a suggestion, I think a great collaborative deal site could be one where the general public cannot join or view posts, where a member must register their eBay account(s), and where a majority of the community can move to remove abusive members (lurkers and resellers). It may sound/be elitest, but seriously, think about it. Instead of my credit card being used/stored at 50+ sites, it could be stored at a single site. A single site developed by the bright minds of Woot, FW, SD, and the greater retail community. Developed so that retailers can target specific consumers. Instead of cramming the unsold, discontinued stuff into a trash compacter, Home Depot can instead find out who is remodeling their home and offer fantastic deals to them, instead of wasting raw materials that are now running out... solving the energy crisis!
Legal mumbo-jumbo - this idea and the system behind are legally protected and are to now be considered patent pending. Thank You.