Yes, we have one for each child. Opened them up as soon as they were born and issued SSN's.
These should be considered long term investments. If you start early, and have MORE THAN TEN YEARS before college, they are a great investment. You can set them up with different savings goals.
We put in $100 per month into each child's account.
DS6 currently has close to $10k
DS4 currently has close to $8k.
Since we started early, and do monthly contributions, we are "dollar cost averaging" which is the best way to invest. Putting a huge lump sum in all at once is a bad idea. Since we began, we've lost a bit of money, but the market bottomed out fairly early in our investments, and now as it goes up and up, their accounts are increasing steadily in reflection of the market. I plan to re-distribute the accounts into less stocks and more bonds as they approach high school.
We are using Upromise's 529 accounts along with the Upromise program. To date, we've earned approx. $3000 in "free" money through Upromise, via merchant contributions. Every time I shop online, I get anywhere from 1-15% in a matching contribution deposited into our Upromise account. Quarterly, those funds are divided and transferred into the kid's 529's. It's a great program.
And, 529 plans do NOT have to be used for education. They remain TAX FREE when used for that, but if your kids choose not to go to college, or get scholarships, or whatever, you still can withdraw the money and do whatever you want with it, but you do pay a tax penalty. I think that's fair.