It was suggested by as many as TWO (!!!) people in a thread in Stage Forums, so here's a topic for those who are getting married and those with experience in either gettin' hitched or those who have worked in a field involving weddings. As always, remember that experiences will vary and to take it all with a grain of salt.
Personally, I worked as a wedding DJ for about ten years and also got married myself about three years ago in a ceremony that went pretty darn well, if I do say so myself.
Some tips off the top of my head...
-Budget. Figure out how much you can spend, and then budget yourself for a few thousand LOWER than that. At some point in the planning you're going to get hit with some costs you hadn't thought of, and the extra cash will most likely get spent. For example: in my own wedding, after we had paid the deposit and signed the paperwork with the reception hall, we discovered that not only did they not have enough china for dinner, what they did have was old, cracked and generally disgusting. Our options were then to decide between paying a premium to the catering company to have them handle it, or to purchase some moderately nice china in bulk, use it once and then donate it to a local kitchen for a few hundred bucks less than the caterer. Just like that, nearly $1,000 went to dishes we used once and never saw again.
-Ask questions. As described above, had we known the hall didn't have adequate dishware for our needs, we may have reconsidered going there, and the same goes for the caterer. People who work around weddings are used to hearing a billion-zillion questions, and if they aren't willing to answer a few regarding resources and costs, don't work with them. Even if you - or your family - has an unlimited amount of cash, ask questions and look to get solid answers. If somebody you're thinking about hiring for your wedding can't answer something logically or respond by looking for specific numbers in order to give you an estimate, they're eventually going to try and screw you at the last second when you don't have a choice. I've seen the nicest-looking old lady florists double their price hours before a ceremony because of bullshit reasons.
-Guests and food. The average number for people who will RSVP positively and then flake out on the day-of is around 10 percent. HOWEVER - if you've been RSVP'd for 200 guests, plan on food for 200. It seems like an easy way to cut a few bucks, but the look of humiliation on the faces of a bride and groom whose guests didn't get any food is very, very sad. It's like they're looking at the rest of their lives stretching out in front of them as nothing but failure and it adds a real tinge of sadness to the entire night. I've only seen it a few times, but it changes the entire tone fast. Just spring for the food, and even making sure you've got extra can't hurt. A drunk, fat guest wanting to stop at a drive-thru on the way home is no big deal. A guest leaving your wedding early because they're starving will turn into all you think about the rest of the night, and all people talk about later on.
-Entertainment. If you're going for a band, look for a band with plenty of wedding experience, preferably one you've seen before who fits the tone you're looking for. If you're going for a DJ, it's also best if you've seen them work before. 99.9% of DJ's will be carrying cards with them, so in the year or so before you get married (and you DO have to think about it that far ahead if you want to book somebody decent) pay attention when you're out and about or at other weddings.
When hiring a DJ, you should look for somebody in the age range between 25-29. At that point they have most likely been doing it for several years, have experience in reading a crowd and keeping them entertained but are also professional enough to maintain the right mood while enjoying themselves. DJ's younger than 24 will probably hit the booze too hard or play poor music choices, and most DJ's older than 30 are failures who were pooped out of the radio biz who will wear cheap, ill-fitting tuxedos with bright tennis shoes (because it's FUN!), try to get your guests to do hula-hoop or limbo in the middle of your reception (it gets the party STARTED!) and play every C'mon Ride The Dogs Out Mambo #5 you ever thought about killing yourself after hearing. The above is not a tried-and-fast rule, as I have seen DJ's who legitimately continue doing it forEVER because they enjoy it, but beware of what is described above as the worst traits in a wedding DJ. And don't be afraid to ask if it would be possible to stop by one of their receptions to check them out if you're going in blind. It puts them on their best game, and in my own experience most couples are fine with somebody stopping by their reception for a short while if they do it after dinner, because they know all too well how hard it is to find somebody for this stuff.
That's certainly long-winded enough for a first post. Further advice/commentary from others and specific concerns - GO!