Jen replied:

>> Did you use any veggies? Veggies like mushrooms, asparagus, onions,
>> etc, need to to be sauteed or grilled or whatever to drive most of the
>> moisture. You're other problem is using milk. Milk is mostly water.
>> Use cream instead. At the very least, use half n' half, but not milk.
>
> No vegies. I didn't have any cream, but I always have milk. Maybe I'll
> try less milk next time.

It just so happens that Cooks Illustrated tackled this exact problem last
year (and I just got around to reading about it yesterday -- I get their
end-of-the-year hardbound compilation of the year's magazines).

Their testing agreed with what notbob said: Although eggs and milk work fine
in the absence of any other ingredients, the second you add anything else,
the milk becomes a problem. Decreasing the amount of milk didn't solve the
problem, because then the eggs became rubbery (and there was still a problem
with excess liquid). The CI solution was to use half-and-half.

Bob