Room requests are very subjective- as others have stated, what is important to your family? Being close to the lobby (Marketplace/Pool). Close to Epcot? A full balcony (only 50% of the rooms at BC have full balconies)? A day bed?
Here is some info from the FAQ page of the Beach and Yacht Club thread. If you haven't been over, I invite you to check out the first page of this thread for lots of info about the resort.
You can click on the link in my signature.
Dee
Will I have a full balcony?
Almost all of the rooms at the Yacht Club have a full balcony. A few rooms have extra large balconies that may be shared with another room.
About 50% of the rooms at the Beach Club have full balconies with a table and two chairs. The remaining 50% have standing or "Juliet" balconies.
If you are staying at the Beach Club and a full balcony is important to you, you should have "Full balcony, please" as your first or only request.
When you check-in at the desk, ask about your balcony and if you are not happy with it, ask if there is a full balcony available. CMs will try their best to satisfy you. Don't do the advanced online check-in. This is for guests who will just pickup their key and go, no questions asked and is not designed for people who may request changes to their assigned room.
Here are a couple of pictures. The first one by pittpantherfan shows BC patio, full and Juliet balcony rooms.
The second picture by Natebenma shows a full size balcony:
Will my room have a daybed?
Some rooms at the Beach and Yacht Club have daybeds. You may request a room with a daybed, but it is not guaranteed. You may also request a rollaway cot to your room when you arrive. This is provided free of charge and is subject to availability.
There are two types of daybeds - one that fits a normal sized adult and the other that is best suited for a small teenager or a child. There is no way of knowing at the front desk which type of daybed is in what rooms. It's totally luck of the draw and the CM can't tell you which is in your room if you get a room with a daybed.
See Post #7 (Beach Club) or Post #8 (Yacht Club) for pictures of the two types of daybeds and various configurations of them made up in the room.
How do I make a request on my reservation? How many requests should I make? What should I request?
You should note any requests on your reservation through Disney's CRO (Central Reservation Office) or your
travel agent can add it when your trip is booked, or anytime thereafter. Requests should be made no later than 2 weeks before you will arrive at the resort.
Please remember that requests are not guaranteed.
The fewer requests you have, the more likely there will be a room available that meets your most important preference(s).
Your best bet is to request what you want in words, not room numbers. The chance that a particular room will be available during your trip is not as likely as finding a room that satisfies your room preferences. If you request a specific room, and there is someone staying in the room on the day you check in, the room assigner will have to place you in a different room. If they don't know what your priorities are, they will have trouble giving you another room that has the attributes you want.
When you arrive at the resort for checkin, you can ask before you take your keys if your requests were granted, and if not, see if there is anything available that meets your needs. Please note that you should do this through REGULAR checkin.
Online checkin is designed for grabbing your keys and going, no questions asked, so if there is a possibility you will ask for a room change, you shouldn't do this.
Requests vary because what is important to one family may be different for another family. Some popular requests are full balcony at the Beach Club, a day bed, close to lobby (or elevator or Stormalong Bay), close to Concierge Lounge (if you are staying club level) or close to EPCOT.
Should I checkin online in advance or wait until I am at the resort?
As noted in the responses above, if you don't have any questions and if you are going to just grab your keys and go, then you are great candidate for the online checkin. If there is a possibility that you will ask for a room change because you are not satisfied with the one that has been assigned to you, then you should wait until you arrive at the resort to check in.