From my personal web pages:
Mandatory Standards
These are songs which you pretty much have to know if you're playing bars, parties, etc. Party songs that an audience will want to hear. It would be a mistake to assume that playing these songs will "make it" for you, but not playing them (or at least knowing them) is also a mistake. And, in my opinion, it's either an arrogant or lazy mistake. They're pretty easy songs to learn and play. I've come to believe there are five of these songs (though, I could be convinced about a couple of others):
* Mustang Sally - But not the twenty-minute rendition, please.
* What I Like About You
* R.O.C.K. In The USA - Yes, the medley is obvious.
* Play That Funky Music White Boy
* Brown-Eyed Girl
I might be inclined to add Sweet Home Alabama, Hella Good and I Will Survive to that list.
Then I go on to talk about sure things and vanity songs. Sure things is a *long* list, but it changes a lot, both from band to band and with time. I remember a time when Smoke On The Water was a sure thing. I wouldn't even consider it now. Some that I would consider would be Love Shack, Tush, Gimme Three Steps and Walk Like An Egyptian.
Vanity pieces are a little odd. If you have a solid set otherwise, you should throw a few in. Of the ones you try, most will fail. The ones that succeed, though, will likely be the ones people remember you for. But none of them will succeed if people don't give them a chance, and that means having a solid set of sure things and mandatory standards.
You don't work music, you play it.
Discipline is not the enemy of fun.