I voted legoland but didn't have chance to comment yesterday sorry.
We have taken Rio to CBeebies land but found we still needed to go around the rest of Alton towers to make a full day of it really as there aren't loads and loads of rides. (However he was only 2 so an older child may stay interested for longer)
Last year for his birthday we went to legoland and stayed overnight in their pirate themed room and it was great. We had 2 days park entry and definitely needed both days to get around everything. The kids entertainment on the night was great fun for them, the rooms are lovely and the buffet dining wasn't too bad either. We went midweek to avoid busy times too, and we didn't have to queue on anything at all! We sent them an email saying we were visiting for my son's birthday and they put his name on the birthday boards around the park and put a cluster of 3 balloons, a birthday card and a Lego gift in our room on his bed for our arrival which I thought was really nice.
I wasn't sure if cbeebies land would be that big, so thats useful to know. She'll be 5, and she's fairly tall, so would be able to go on other things. Whether or not she would want to is an other story!
How much did you pay for your legoland trip if you don't mind me asking? X