Obviously, select according to your budget, but keep in mind that, in many cases, your entertainment will make or break the evening. Much of the success of your event will be contingent on the quality of your entertainment, so choose wisely. Soloists seem to work best at the ceremony. For the wedding reception, the most popular choices seem to be a DJ or a band. While both have specific advantages, DJs, due to their versatility, seem to be the best value overall.
Bands can offer a special appeal because they are a LIVE show.
Also, some bands will have a large following or big name in your area. The fact that they performed specially for your reception make it all the more memorable. DJs will provide a host to run the event, music, lights, and special effects to enhance the special moments. A DJ's best asset is versatility. Not only can they make abrupt changes in era, periods, and speed of the songs, but if they have a large library, they should be able to accommodate any and all tastes in attendance.