Congrats Zahir.
I hardly wear jewelery, so rings tend to come and go with me. I do have a white gold ring with a diamond that someone very special bought for me, and I like to wear that when I think of her, as it was a good time for both of us and signified something that's enduring and really quite wonderful. Heh.
I've been bought rings before, by other girlfriends, but they were more of a token gesture than one with true meaning, I think. I'm not one much for the gestures, myself. I prefer something simple.
I do, however, have a claddagh ring that my mum bought me for Christmas last year. It goes onto my little finger and I do love it so; it's silver and looks great. The band itself is a woven celtic type, rather than plain silver. It's pretty. I have, however, since passed it on to someone else who is keeping it for me. Nice and safe.
As for Willow and Tara; I'm not sure they'd choose rings, exactly. But I know they'd choose something symbolic of who they are to one another, rather than a big ol' expensive ring.