I've done:
The Big Blue Hotel - Blackpool.
The Safari Hotel - Chessington.
Both Alton Towers hotels.
Newport Bay Club - Disneyland Paris.
Hotel Port Aventura - PA.
The Colosseo - Europa Park.
Abenteuer Hotel - Heide Park.
I suppose Days Inn at Kings Dominion was kinda on site too, but in no way was it themed so I won't count it.
Out of those, I'd say the Hotel Port Aventura and The Colosseo were the best. Best perks, best location, amazing food, nicest rooms etc... And the theming in the Colosseo is STUNNING!