Recessed lighting fixtures are relatively cheap compared to the most popular decorative fixtures and therefore I believe contractors and amateur designers have come to rely on them for general illumination in addition to task and accent lighting. I think this is a mistake but this is the first decision you need to make before getting wound up in the layout.

I like to first locate the task lights at counters, etc. and use 4" line voltage PAR 20 halogens where possible because they are the least expensive. They should be spaced between 32" and 48" apart. Some of these fixtures might need to be a "wall washer", a "35 degree adjustable", or a "pin-hole" type, depending on your personal tolerance for light scallops on kitchen cabinets above work counters, tables not centered under a downlight, and the amount of a lamp visible when seated at a dining table.

Some of the special types mentioned above are only available in low-voltage models, especially if the fixture must be rated for direct contact with insulation or air-sealed when below an unheated space.

Complicated; you bet!

After the task lights are located I like to light the walls where owners will most likely put artwork and photographs. This is more important to some owners than to others. But I believe rooms appear larger and more interesting when the walls are well lighted rather than the floors. This is even true in hallways.

Some owners prefer decorative wall sconces as a way to light some walls and hanging lights over dining tables or islands. The size and power of the sconce should be carefully selected for the room and you need to be careful about blocking views with hanging lights. If you are tall you get tired of moving your head to see other people but if you raise the fixture the light source can become too visible.

After locating the task and wall lighting, I try to fill in where there might be a dark area or where a decorative carpet or floor area needs emphasis. I try very hard to avoid a downlight over people's faces, especially in front of a mirror.

Electricians will often tell an owner that only fluorescent lights are allowed in a closet but recessed incandescent lights are allowed if the fixture is 6" or more from the "storage" area defined by the NEC and there is a lens on the light. This basically means that the closet must be deeper than 24". (Surface incandescent lights are allowed in a closet if the fixture is 12" or more from the "storage" area. This basically means that the closet must be deeper than 28".)

I have had some clients (especially those who entertained a lot) who loved recessed general lighting so much that in addition to task and wall accent lighting, I put line voltage PAR 20 downlights on a 4 ft grid throughout a living room or a family room. This requires a lot of heavy duty dimmer switches.

I've never had two owners who had the same taste in lighting or anything else for that matter. You can only hope that one spouse takes the lead in this matter.

Wow thank you so much, that is extremely helpful!

The site in the link will help you too. The person who owns that site used to post regularly in the kitchen forum, but I don't know if he still does that. As mightyanvil says, everyone has different lighting tastes.

Here is a link that might be useful: how to lay out can lights

You can only hope that one spouse takes the lead in this matter.

Isn't that the case for everything? ;)

That is a terrific site. Thanks for pointing me in the right direction!

I don't want to offend anyone but someone should warn people to be skeptical about using the site linked above. The author might be a competent electrician but, in my opinion, there is some pretty questionable lighting design information on the site.

I'd love to know why the primary layout example uses "a typical recessed can with a 40 watt R-40 flood". I don't think such a lamp is even available. A 40 watt R40 incandescent flood (if anyone makes it) would fit in a 6" diameter recessed fixture and wouldn't throw much of a beam on the floor. A 40 watt R40 fluorescent flood lamp (if anyone makes it) would be too bright to be appropriate for a typical home.

A 75 or 100 watt R40 incandescent or an 18 or 23 watt R40 fluorescent would be more appropriate but only if you wanted to be sure to be able to see the glare of the lamp the moment you walked into the room. 6" recessed fixtures are appropriate for commercial use with more expensive deeply recessed lamps.

Actually, I don't think the old R40 reflector flood lamp design is at all appropriate for homes today; there are simply too many other better choices. For fluorescent recessed lighting I recommend fixtures designed to use fluorescent lamps specially designed for overhead recessed use that can be dimmed without reducing the life of the lamp. For incandescent recessed lighting I recommend 50w. PAR 20 line voltage lamps or 35 to 50w. MR16 low voltage lamps in 4" fixtures. Sometimes a 5" fixture is needed to cover more area or when insulation contact or sir seal requirements prevent the smaller fixtures from being used.

Recessed lighting has the primary benefit of providing strong focused light without the source being obvious or objectionable. It would be a very poor idea to let the lamps be seen by using large diameter fixtures with large reflector lamps as was sometimes done in the 60's and 70's. It's great to see those awful things get pulled out in renovation projects.

Here is a link that might be useful: a basic lighting guide