I agree with the those listed so far but I feel the list should be limited to offers that almost anyone can get in on and not just a lucky few that happen to , well, get lucky. And deals that are guaranteed and not just "maybe".

ex: I would not have listed the Chase Sapphire 100k as this was only good for about a day (or was it a weekend) before it was shut down as they realize their mistake. Only those lucky enough to happen to have the time to read certain forums and at a specific time got in on this. I was busy that weekend and by the time I read about it --too late.

Same goes for the Amex 10,000 points for each added user up to 5. Note: I manage to get in on this last night but only after 5 calls and loooong wait times each and everytime. Now some have posted Amex may not even honor the points for those that made it in as it was TARGETED ONLY for people in Argentina, So, this is still not a done deal (but hopefully--fingers crossed).