To pay you your $1000/wk, all they do is place the $675,000 into a guaranteed investment that pays out weekly (i'm guessing here), hence really you're still only getting the $675,000. By doing this, it also guarantees that you'll get the $1000/wk for 25 years because what if in 2 years they just say, yeah, we don't have any money... then you're hooped.
I say take the 675,000, spend 1/4 of it as you wish and put the rest into real estate that you can rent out and receive cash flow, OR other investments. Oil stocks were and are a good bet for investments. Avg annual rate of return is 14%.