The right entertainment is vital, it can make or break a party.
You can have the best of everything at your event, but what is the most visible is your entertainment. If your guests are being entertained and are having fun, it will show in your pictures and video. If they are not having a good time, you will see that too.
Price, while a consideration in your budget, should not be the sole determining factor. Sometimes you may actually end up getting what you paid for. Vice versa, the most expensive is not always the best.
Usually, the best way to find the right entertainment is through a referral by someone that has attended a performance or getting a business card from an entertainer at a party you attended.
Once you get a referral, the best thing to do is to attend their next event to see them live, or see if they have a video tape of their performance. The most important thing is that you feel comfortable with who you are booking and that they understand what you are looking for.
How to Choose:
Large company vs Independent
If you hire a large company, they usually use a preset formula. The positive aspect is that all their performers do the same things(the cookie cutter approach). The negative aspect is that your event will look just like everyone elses' and they will often not be able to adjust their show to cater to your crowd. They also have more people working for them, so they have additonal people to cover in case something happens. But, you may not always know who will show up at your event unless you specify a specific person.
Independent Disc Jockeys tend to go out of their way to customize your event to your tastes. Whoever you hire is usually the one that will be performing at your event. They also have industry contacts, for coverage in the event of an emergency.
Don't let the appearance of lavish office sway your decision. While the office may look nice, it also means they have fixed costs that need to be covered. Usually by the price you get charged.
Other helpful hints:
Plan early, whether its the hall, entertainment, photography, video, florist, bakery, caterer, etc.
Usually, the most popular places and entertainers get booked quickly.
Make sure your entertainer has insurance.
Make sure you confirm all your bookings.
Make sure you go over specific details to ensure that they are carried out to your liking.
Also, make sure any special requests are cooridinated between all the necessary parties(for example, some catering halls do not allow the use of fog machines, because they set off smoke detectors).