Mmm, I love crystal light! I think my favorite is the Raspberry Ice
As for it counting as water, I only know what WW recommends -- that you can count non-water, non-caffienated beverages as HALF of your daily water intake. So I can drink 8 glasses of Crystal light but should only count 4 of those towards my daily water goal.
I don't even know why it's a rule, though. At least it's something, you know?