I went to Busch Gardens in Tampa in December - it was really fun. Lots of fun rollercoasters and lots of animals.
I'll second the PP who said Clearwater Beach. It's about 40 minutes from downtown Tampa to Clearwater, and about 15 of that is spent driving on the causeway - which is kind of fun in itself. Or maybe that's just me, we don't have causeways in Iowa.

Anyway, Clearwater Beach is really nice. It's clean, lots of neat shops, good food and the most beautiful sunset.

My parents live there, and I could probably spend 90% of my time visiting them at the beach because there's always something to do.
My parents are big fans of Sea World - they like feeding the dolphins and stingrays and all that. I've never been there though, I'm hoping to go in May when I visit them again.
ETA: If you and your daughter like shopping, International Plaza in Tampa is amazing! My mom and I spent pretty much an entire day there in December. They've got tons of great stores and some really great food places. Plus, who can resist cheesecake from The Cheesecake Factory?