Brightness is a matter of opinion; coverage is less so.
I think poorly designed lighting is WAY too common and it's painfully obvious when I walk into a house or room that some silly "designer" (all too common in our area) picked the lighting locations willy-nilly and some silly electrician followed the lead, more or less.
In fact, when the electrician started cutting holes for our lighting, he had markings that left up to 1" error. I told him to go do something else while I plotted them all out with a .5mm pencil and drilled the pilot hole.
End result: beautifully covered lighting that goes as un-noticed as carefully chosen paint colors and careful attention to detail on moldings... except that the end result is pleasing even if one can't say just why.
I think the best "look" (and ideal in terms of heat and brightness and such) is 6" cans (such as Cooper / Halo's 7ICT stuff at a mere few bucks each at Home Depot) with an attractive baffle and bezel. I prefer simple in those categories, but that's just our style. There's some shots of one room
here. There's more stuff
here if you click into "Remodel" or "Home Automation" and poke around. You can see them going in a bit in "Remodel".
The decent fixtures have auto-shutoff if they overheat, so if you put the wrong bulb in, you'll know it.
I run Philips 65w bulbs in the 6" cans I put in our current house. I followed the 6' rule, since we have 8' ceilings. When decent dimmable CFLs are available at a decent price, I'll probably move to them. I've seen them encased in what looks like an R30 body, which I think looks much better than the curly-cue in the socket.
I use 100w R40s in entryways and hallways in 6" cans.
I use 4" cans for art-lights in every room and for sinks and potty in the one bath we've remodeled. I started with AC 4" but have replaced many of them with low-voltage DC now. The DC light is wonderful for sinks and desks and such.
Note also that you can adjust the depth of a bulb in the can. I keep the R30s recessed a bit in most areas but recessed a LOT in the master bedroom as it softens the light a lot. the R40s are actually running at or beyond the edge of the bevel; hence one light for a given area - though with as many as three sets of art spots in a single stair landing, so there is no lack of light if desired.
I run all the lights with Insteon switches (previously on X10 Switchlincs) and they turn on to 70% bright or less - except the R40s, some of which are 100%. This gives a softer look and leaves room to get brighter with a second tap on the switch. So... back to your last question, I guess that's somewhere in the 45w per 6 square feet of floor, capable of 65w - plus the art lights that are anywhere from 2x25w to 2x50w and at least one pair per room.
HTH a bit... should'a put that on my site, I guess.
h34r: