I have a 4 year old and 2 year old and I've done a lot of reading about this and here is what I'm doing, and what I believe the best advice is.
First it depends on how much you make. If you are in the 15% tax bracket or lower then it's pretty simple. Do your 401k up to the company match, then max out Roth IRAs. If you still have money left over you can do a 529. But if you are in the 15% bracket then chances are you won't have much left over after putting $11,000 away in Roths.
Now if are in the 25% bracket the same rules apply, but slightly different. 401k up to the match, Roth IRA, then you put extra money into your 401k until it's maxed, then save in a 529 or education IRA if you still have money left over.
Now, let me explain why. The college aid forms ignore the parents retirement savings, but they include everything in a 529. So if you have money in a 529 it will count against you, but if it's in a ROTH it will not count as an asset you can use to pay for college. So if you have money in Roths and 401ks you will qualify for more aid.
If you are in a higher income tax bracket (like me) the strategy is to fund Roths and 401ks to the max. Then you get the maximum number of subsidized student loans you can get. Then you liquidate your Roth to pay for everything above subsidized student loans.
When your child graduates and it's time to pay back the student loans you take out a home equity line and use that to pay off all of the loans. Then you use your 401k to pay off your house once you've retired and you are in a lower bracket.
This strategy minimizes the taxes you will pay over your lifetime but if it's too much of a hassle you can just put after-tax money in a 529. But for me I pay 6.45% New York State tax and 28% Federal tax. So it's worth it to me to max the 401k and save 35% in taxes vs funding a 529 with 65% less money.