There is an extreme difference of opinion on the issue.

I, personally have a wonderful pair of natural wool colored (cream/ecru) hand-knitted hose done for me by the lovely and talented Ms. String from this forum. I wear them a lot when I need to dress up. I think they are wonderful and I like them a lot. I wore them to dinner for Valentines day at a very "tony" restaurant.

However, there are others who feel that white or cream hose at any time at all, and all the moreso in a more formal setting, is an absolute horror.

IMHO, and this is just me, I'd say wear what looks good to you, and spent maybe three to five minutes worrying about what is "correct". Look at pictures on this forum, look at your budget and purchase (or make) an intelligent decision accordingly. Respect other peoples views, understand that no matter what you do, SOMEONE will think you've made a mistake, and carry on.