Offer is expired! There is a new 30,000 Starpoints sign-up promotion with the Starwood Preferred Guest American Express Card after $5,000 in spending within 6 months. First, they will give you 10,000 bonus Starpoints with your first purchase. Second, spend $5K within 6 months and get another 15,000 points. You get 1 Starpoint per dollar, hence another 5,000 Starpoints for a total of 30,000 Starpoints once everything is done. More importantly, there is a $0 annual fee for the first year, then $65 a year after that.
Starpoints is great for converting to frequent flier miles since you could get 20,000 Starpoints = 25,000 miles = free flight ticket. Hence, you could end up with a free flight ticket + 10,000 leftover Starpoints with this hot promotion.