There are lots of great options out there! As many people have mentioned, They Might Be Giants have some great CD's (Here Come the ABCs and Here Come the 123s) which kids and adults can both enjoy.
For Bedtime, the Rock a Bye Baby line of CDs is really interesting. Each CD takes a poplular band- The Beatles, The Cure, Depeche Mode, Madonna, etc - and instrumentalizes the music to give it that nursery feel. You end up with some soothing music that sounds like songs you know and love.
In the pure kids genre, the new Fresh Beat Band plays some really catching tunes. Kids love to watch the show and their new CD is update. The singers are quite good- you may even find yourself listening when the kids are out of the car.
Lastly, on the world music side, Dan Zanes, formerly of the Del Fuegos, plays some fun danceable music that parents can enjoy too.
We've all had our share of listening to the LIttle People, Barney and Dora - it's nice to balance it out with music parents can enjoy too!