Should Women Help Choose Their Engagement Rings?

I recently got a letter to my wedding advice column from a guy who was upset that his fiancee wanted to help pick out her engagement ring. After years of experience, she didn't really trust his taste. This brought up a whole round of conversations on our wedding blog.
Some people stand by the idea of an engagement ring being a surprise, and a present from the groom to the bride. Others, see it as the bride's most expensive piece of jewelry, something she'll wear everyday for the rest of her life.
Given that most women work long after marriage, they will probably be helping to pay for the engagement ring, so why shouldn't they help pick it out?
What do you think? Did you help choose your ring? Would you like to have done so or is it a romance killer?