|I've been happy with Country Save.
As you can see, I think you have some good HE options. Not every detergent works for every washer with every water type, though, so pick whatever is easily available and seems like the best option, and stick with it until you have problems, which you likely won't. You'll read about detergent problems on this board, but I truly believe that the vast majority of people are just washing happily with whatever they started with--they just aren't posting to say how happy they are. :-)
Just remember to use 1/4-1/2 of the recommended amount (I believe this is plenty for regular laundry as well, but it's esp. important for the diapers that are getting washed so often). You can also do something like wetting your diapers before they go into the machine (or after you've put them in) to make the machine think there's more and thus use a little more water to wash/rinse them.