I'm not a party animal but I've been dragged along to a few events from time to time!
Here, for what they're worth, are my thoughts:
Live music is always better than any disco. (Well, it is if you book a decent band, anyway!). It will also make your party stand out from other parties which your guests may have attended.
A formal, sit-down meal?
No way! You want people to relax and start enjoying themselves as soon as they arrive. Go for a buffet.
Entertainment?
While there are some technically good magicians out there, very few seem to be genuine 'entertainers'. Allow everyone to have a break from dancing and socialising by engaging the services of a good comedy performer. (That could be 'stand up' or, for example, it could be a ventriloquist with a decent comedy act).
A Casino Royale theme?
Well, if you really want to, I suppose but a good party shouldn't need any theme.