I've already been to two seders and this evening I'll be hitting my third. There have been a number of outstanding take-out dishes:
Dark chocolate-covered matzo with sea salt from City Bakery: This just knocked me out. I'm sure it's not kosher for passover, but it sure was delicious.
Gefilte Fish from Citarella: I'm still not a gefilte fish convert, but Citarella's gefilte fish actually tastes like fish and not jellied seafood matter. My sister-in-law served it with real balsamic vinegar, which kind of worked.
Matzo ball soup from Yura: Phenomenal matzo soup featuring light and fluffy matzo balls and flavorful, well-seasoned broth that tasted like a chicken had actually been used in making the soup.
This is probably not useful information for this year unless you hold a seder on the third night of Passover, but there's always next year in New York or Jerusalem.