If you're planning a wedding reception you will almost certainly want music of some sort; and there's nothing that gets a party going like a live band.
A live band is something to watch, listen and dance to, and the interaction between a good band and the audience takes dancing on to a new level, making the whole event more participative for everyone.
There are many bands that specialise in performing at weddings but that doesn't mean that any other bands are not suitable. The important thing with any band is to do your research. Make sure you know the kind of material that it will be playing. Will it be suitable for your guests? Will it cover a range that will involve all your guests? Perhaps your guests all like a particular type of music in which case you'll want a very particular band.
Some bands are very specific in that they only play songs by a particular artist or band; so-called tribute bands e.g. a Beatles tribute band or perhaps a Darkness tribute band. A tribute band could be ideal for you but if you have a wide range of guests then it might be better to consider a more general wedding band.
You should make sure that your band is licensed, where necessary, to play the songs that it plans to play. Many bands are not and this is illegal.
It's also worth asking the band if its equipment has undergone a recent portable appliance test (PAT).