Amusement park.
Rides are more important than theme imo.
Theme is helpful as it creates an atmosphere and adds to the escapism, but ultimately I go to a park to be thrilled.
Rides can look good but if they don't ride well, then there's no point.
I'm going to use Rainbow Magicland as an example.
Here's their rapids ride, Drakkar.
[youtube]http://www.youtube.com/watch?v=rOfzvKqe8hU[/youtube]
Doesn't it look wonderful? Those massive statues look so impressive. However, the ride itself was bland. Hardly any splashes, no thrills... it was dull.
Search for Rainbow Magicland POVs on YouTube and you'll soon realise that things that look pretty don't necessarily ride well. I'd rather ride an exciting, choppy rapids in a car park than one that does nothing apart from looking pretty. One of the best rapids rides I've been on is the now-permanent travelling rapids ride at Lightwater Valley!
It's the old "you can't polish a turd" expression once again. If something is crap, you can't hide it under a bit of lipstick and get away with it.
There are exceptions to the rule (like Big Thunder Mountain at Disney for example), but generally an amusement park will have higher quality ride experiences over a theme park imo. A theme is just "nice".