Usually depending on the age range of the Audience. Older and more formal audiences such as Weddings etc, I tend to use compilations (Greatest Love Songs ever, Greatest Love songs ever, ever vol 2

) etc you get the picture!. More informal / younger audiences just get a selection of easy listening chart / ex chart.
If there are a lot of Kids at the function then I tend to skip the boring background music bit and use the 1st 30 mins to 1 hour using this time to entertain the Kids at the venue (Saves the embarrassing "Can you play steps please" request when the adults are dancing to something completely different later in the Evening). This was a tip from Karen, for which I will be eternally grateful for

since it works wonders and stops the little

from running riot and getting bored and also increases your professionalism at the same time.