Our next decision is what the deck configuration will be. Monohulls can be roughly divided into two categories: center cockpits and aft cockpits. The names are pretty explainatory: in a center cockpit boat, the cockpit is in the center of the boat, and in an aft cockpit boat, the cockpit is in the back.
Although the distinction between a center cockpit and an aft cockpit is far more than aesthetic, I wish to make a quick note on aesthetics: aft-cockpit sailboats look better than center-cockpit sailboats. A center cockpit is much higher off the water than an aft cockpit, resulting in a bulky, wedding-cake-like appearance. An aft cockpit is low and flows into the rest of the boat. See for yourself. Here is a Alden 50, an aft-cockpit boat:
Note that (a) the cockpit is in the back ("aft"), (b) the boat is beautiful, and if you can't see that, you can't be helped. And here is the exact same boat, an Alden 50, but in a center-cockpit configuration:
Although the hull is exactly the same, note that the cabin trunk extends all the way to the back of the boat (compare the number of ports on the side), and that the cockpit is in the middle of the boat on top of the cabin trunk instead of behind and flush with it. The result is that the you sit up much higher and the boat simply doesn't look as good (although an Alden 50 could never look bad).
But enough with aesthetics and on to the practical differences between a center-cockpit and an aft-cockpit boat.
As a matter of sailing performance, the edge goes to the aft cockpit for two reasons. First, because the center cockpit is higher up, it has more windage, which means the boat (as opposed to the sails) catches more wind, and the result is that the boat does not sail as well, especially towards the wind. Second, because the center cockpit is higher up and closer to the front of the boat, it catches more spray from the waves. It is simply less protected up there than in the back.
As a matter of interior accommodations, however, the center cockpit is the clear winner. In an aft-cockpit boat, the interior more or less stops where the cockpit begins. But with a center cockpit, the interior goes all the way back. The result is that, in the back of the boat, you get a huge master suite with standing headroom that is nicely separated from the rest of the boat. The two Alden 50's are again illustrative. Here is an interior drawing of the aft-cockpit Alden 50:
I'll explain what is going on in this drawing. Moving from right (the front of the boat) to left (the back), there is, first, a bed that sleeps two people, their feet together and their heads separated, (this is called a V-berth). There is then a head (bathroom) on the top of the drawing (left/port side of the boat) and various shelves and closets on the bottom (right/starboard side of the boat). That whole area (bed, closets, bathroom) can be closed off from the rest of the boat, forming the first stateroom (bedroom/suite). Next is the salon, with two settees (couches), one on each side of the boat, and a folding table in the middle. Moving further towards the back of the boat (to the left of the drawing), there is the galley (kitchen) to port and a second head to starboard. At the very back of the interior, there is a desk/office area to port and a double bed to starboard (note that the bed can only be accessed from the front, so you have to crawl onto it, like crawling into a cave). The double bed can be closed off from the rest of the boat, forming the second stateroom. The interior stops at that port, as the cockpit consumes the back on the boat (far left of the drawing). For a sense of scale, the settees and berths are all about 6'6" long.
And here is a drawing of the center-cockpit Alden 50:
I wish this one were oriented the same way as the first, but that would be too easy. Now, the front of the boat is the top of the drawing, the starboard side is the right of the drawing, port side is the left, and the back of the boat is the bottom of the drawing. This orientation is actually a bit easier to explain. The front half of the interior is pretty much exactly the same as in the aft-cockpit version. You have the first stateroom up front with a V-berth, head to port, and storage to starboard. Aft of the first stateroom is the salon with settees on each side (this one happens to have chairs to starboard) and a folding table in the middle. Aft of the salon, everything changes. The white area in the middle of the drawing is the cockpit, so there is no interior there. Port of the cockpit, there is the galley. Starboard of the cockpit, there is the desk/office area and storage. Aft of the cockpit is the second stateroom, and here is where it gets exciting. Instead of a cramped berth tucked to the side as in the aft-cockpit model, the aft stateroom in a center-cockpit boat is an actual bedroom. There is a full queen bed in the middle that can be accessed from the sides (instead of having to crawl into bed from the end), hanging closets and shelves on each side, and a private head. The aft stateroom is separated by multiple doors from the rest of the boat.
I think the interior differences speak for themselves, but to state it clearly: we want a private bedroom, and we are getting a center-cockpit boat.