I myself found Spence to be very very pricey when I was looking for the ring a couple of years ago, just as Jam said its a great place to become educated about rings and diamonds but there are far better deals out there.
Brownie: It shouldnt matter how much you spend on the ring, your asking her to marry you, not the jewelery. But that being said most women do like big sparkly jewelery, the ring I bought when I asked my wife to marry me set me back $4900