What's the goal? Are you trying to start an AL community at this game store, or are you just running another game for your daughters to play in? Is there room in the store for multiple tables? Does the store stock all the D&D products, or just the hardcovers, or just the most current stuff?
None of that is strictly necessary to decide what you're going to run at your next game, but a little forethought up front can keep you from having to re-tool things later. For instance, jasper's idea of running a season tier 1 first, then moving to tier 2 is a solid one, but if you're the only table and there's no room for another table, moving to tier 2 is effectively putting up a 'no new players' sign on your table. In that case, you might be better served running a hardcover adventure, since those allow mixed-tier parties and thus you won't necessarily have to turn away a new player just because that player doesn't have a tier 2 character. Likewise, if the store only carries the current D&D products, running older season material might not help the store gain any sales, which is likely one reason the store wants games.
If all you want to know is 'what's fun?', well, most of it is fun. I'd go with Season One, since there's an energy and freshness in those modules that doesn't always come through in later seasons, but that's just my $0.02US.
--
Pauper