I would say it depends on how you view your finances. If you simply want to get the most out of your money, a Roth IRA is your best bet, especially if you don't have one opened yet. But...if you're in a situation like ours--we have two boys and one IRA opened already, and would like more children--piling all that money into an IRA means that our children would not have distinct accounts for "their" college money, as only an income-earning individual can have an IRA (or maybe it's an adult? I'm not working right now, but I have one. Anyway, I KNOW my kids can't have one.) As far as earning interest and being sheltered from taxes, the Roth is definitely the way to go. Be sure you shop around and find one with the best rates; they vary quite a bit. We are also looking at a 529 plan, which seems to be the most flexible education account available. We do our finances through Thrivent Financial, and they only do the Nebraska plan, meaning we wouldn't get tax advantages in MN, but on the other hand, they've researched the "best" plans and that's the one they've come to. So...if you're comfortable lumping all potential children's money together with what might even be retirement money, I'd say do the Roth. If not, find a good 529 plan--anything that will give you an interest rate that supercedes inflation.
Ohh--someone mentioned penalty on an IRA...the penalty is pretty minimal; we've been to a number (5? or so) different financial advisors and they've ALL recommended the Roth over a 529 IF you don't plan to max out a Roth on your own, for your own retirement. IF you and our husband can contribute the max (5000? this year) to each of your Roths, you should really save that money for your retirement. If that's not possible, then a Roth is a great place for your kid's college; it gets a much better return than the 529. As for online banks--they get much better interest than brick-and-mortar, but they don't compare at all to a Roth--neither does a CD.