For college savings, I prefer target date funds. They're simple, and they become more conservative over time. College funds also typically aren't large enough to warrant more complicated vehicles. This is an option in the 529 plans I've used.
Other things I've done include CD's, Money Market Funds, and higher yielding bond funds (when I'm willing to accept some risk).
Another good option is the direct purchase of treasury bonds, as you have certainty on the expiration date and expiration value. Obviously, this is a better choice in higher interest rate environments than we have today.