We didn't have conventional wedding rings. We had matching surgical stainless steel claddaghs, made for us by his stepmother, who is a jeweler.
My initial engagement ring was a simple band that he already owned, though she later made me one with a 3/4 carat diamond. It was nice, but the fact that it was created for me by someone who cared for me meant a good deal more than the appearance of the ring itself. The diamond was held in by the tension of the band itself, rather than the usual setting, and it fell out at one point due to working with my hands all day. Her response? "It's just a rock, send it back and I'll put in a new one." Diamonds and other stones are pretty cheap to jewelers.
I feel like white diamonds are overrated, and too common to really be special. I have a yellow diamond ring, which I love because the color is so nice, and because it was a gift made for me. I also have a somewhat large amethyst - my birthstone - which I felt was "too big" at first, but it's so pretty that I now see it as "normal" sized. I like both of these rings far more than any rapper's "ice", because they're unique and personal.