Residential Circuit Layout
Lights are typically put on a separate circuit from the receptacles, especially in places where GFCIs are required (kitchens, baths, and garages). This gives the benefit that when a breaker trips, you are not left in the dark. In many cases, #14 wire is used for lighting circuits whereas #12 wire is used for receptacle circuits. Keeping them on separate circuits allows you to use different size wires for each.

In addition, circuits are generally laid out by room, but it's not always the case that each circuit is one room. Adjacent rooms, or similar rooms, may be combined on one circuit, depending on the sizes of the rooms and how many receptacles each will contain. If your living room and dining room are adjacent, for instance, receptacles from both rooms may be on the same circuit, and lights from both rooms may be on the same circuit. Two adjacent bedrooms may share the same (AFCI-protected) circuit (this cuts down on the number of AFCI breakers needed, saving some expense). A great room that's very large may have it's own circuit for receptacles, but share a circuit for lights.

You may want to run additional dedicated circuits for unique equipment you plan to run, like computers in a home office (especially high-end machines), woodworking equipment, etc. There is nothing wrong with having a single receptacle be on a separate circuit in a room, or have half the room be on one circuit and half on another. Since you're doing the work now, when you've already lived there, you know better how you use the space, so set it up so it works best for you (while maintaining code).

Keep in mind any special-use circuits (oven, dryer, water heater, etc) will be their own circuit by definition, as these are usually 240V. Also keep in mind that the kitchen requires 2 separate small-appliance circuits, and the portion of those circuits in the kitchen need to be GFCI protected.

When you do get everything laid out and run, make sure to clearly label the panel. Perhaps even a separate diagram or spreadsheet showing which breaker every single receptacle, light, and switch is connected to. I might even go so far as to diagram where each wire is run through walls and ceilings. Digital files are cheap, and you never know when that info might come in handy. Along the same lines, consider installing conduit and/or low-voltage cable (networking / TV) at the same time; the best time to run new cable is when the walls are already open.