Just wanted to add a quick note... (on another board this seemed to turn into a big debate

)
If you go to Universal Studios (where Halloween Horror Nights is being held this year) during the day you will not be able to experience Halloween Horror Nights. The Haunted Houses, Special Shows, Scarezones, Scareactors, etc...
are only availble during the event (from 7Pm to either Midnight or 2am depending on the night). So the only daylight you might get is between 7pm and when the sun sets. (In the past it seems like I've had about an hour or so of daylight after the event started)
However- there is a day time "behind the scenes" tour. (check out the official website) for about $35.00 per person...this would allow you to see some (not sure on the exact details) of the houses with the lights on. (The scareactors will not be in the houses at this time)
This might be a good idea if you're worried about being scared at night. As others have said, nothings as scary once you've seen it in the light.