With the merger between Marriott and Starwood, you can now link your SPG account to your Marriott / Ritz-Carlton Rewards account and transfer SPG points to Marriott / Ritz-Carlton Rewards points at a ratio of 1:3. Thus the signup bonus of 35,000 SPG points equals to 105,000 Marriott points. If you open both personal and business cards, you can transfer 70,000 SPG points to 210,000 Marriott points. As we expect at some point, Amex SPG Card will be gone, it is your best chance of getting a boatload of SPG/Marriott points if you have never had SPG Card before.
Personal Amex SPG Landing Page: you will receive 25,000 points after spending $3,000 within 3 months of new account opening, and another 10,000 points after spending an additional $2,000 within 6 months, thus a total of 35,000 points with $5,000 spent.
Business Amex SPG Landing Page: You will receive 25,000 points after spending $5,000 within 3 months of new account opening, and another 10,000 points after spending an additional $3,000 within 6 months, thus a total of 35,000 points with $8,000 spent.