The big recommendation is to get a handle on the terminology.

Exhaust is the function you want done.

Cooking produces rising warm (steam, grease, smoke) air.
Hood is an upside-down sink or umbrella shape that the bad air rises into.
The industry often mixes terms up, and it actually doesn't hurt sales. So they may say "Hood" when they mean a whole lot more.
Canopy, as a term, works because it focuses attention on the Hood alone.
Capture Area is another word for almost the same thing.

Make-Up Air, MUA, is the air that comes into your kitchen when you blow bad air outside.
It is a lot of air. It replaces the volume of air you sent outside.
In cold climates it has to be planned for as part of the house system. Windows are often closed.

Duct is the conduit / pipe / tube or rectangular shape channel that your bad air travels down.
Liner is almost the same thing. It actually IS a liner if it matches a special shape of hood... but once again, the industry will use this term "liner" to mean anything that creates confusion.

Duct is made of smooth metal, not corrugated. Never made of plastic (this is Kitchen Exhaust)

Filter is the grease catch that you want to have at the front end.
Filter could be Mesh.
Filter could be Baffle.
Filter can only be that, in outdoor exhaust situations. Charcoal is not an option here.

Blower is the motor that grabs that air and blows it outdoors.
Blower can have spinning propeller blades.
Blower can be squirrel cage.

Insert is a combination of a few things, built as a package that you insert into a hoof and liner.
Insert is a package of blower, filter, switches, lights, etc.

The industry often mixes terms up, and it actually doesn't hurt sales since they get to sell their all-in-one products.
They don't push inserts.

Inline describes a blower located at some point in the Duct.
Inline is not at the duct beginning (front end), and not at the Duct termination.
Remote describes a blower located in a place far away from the kitchen. It can be at the end of the Duct, pulling (sucking) air instead of pushing it down the Duct.

The industry likes to sell more than just a blower. A whole kit. An all-in-one solution. Something that parts fools from money. Consumers who know enough can separate all the variables.
The industry does not promote inline blowers.
Having an inline blower allows the consumer to buy the other parts as separate items.
The industry does not promote remote blowers. Some are promoted as part of a whole kit. They can be bought separately.

Blowers that are not positioned at the front end of the duct are not in your face.
Noise is caused by several factors. The blower being in your face is one factor.

Review:
The industry mixes terms up. They will call anything a Hood.
Exhaust is the big general term. "Will this Exhaust my kitchen air?"

hth

Thanks- very detailed! I might have to reread this one a few times! :-)

Just went through this. I am no expert, but may be qualified to do the intro for the "idiot's guide" (don't take that personally.) This is what I have gathered from hours of gardenweb..maybe it'll give you a headstart.

This is in addition to the concise and accurate information that has already been posted-

First, figure out what size...42", OK. You got that one already.

Second, figure out how much sucking power you need (standard formula has to do with adding BTUs of your burners and dividing by 100=# CFMs you need.) Not that simple, though. You may want more, depending on your situation. Variables include type of cooking you do (wok? grill?), height of hood above range, whether there are side cabinets to help direct air flow, efficiency of overall setup. Your range may suggest the CFM to choose. (In your note above I think you're thinking 1000+. 100 would be really quite weak.)More power=more noise potentially, but I believe a stronger blower running at 1/2 strength is quieter than a weaker blower at full strength-that may factor in as well.

Next, decide where the actual motor will be. In the hood itself (internal), or outside the hood (inline, i.e. in your attic or some other space, or exterior, i.e. mounted on roof or an outside wall?) As noted above, internal is the most simple, but depending on your set-up you can minimize noise with an external blower. This decision may be made for you-maybe your only choice space-wise is internal. Your choice also affects the price.

Next, pick baffles, mesh, squirrel cage. These are the filters. Your choice will affect sound, ease of cleaning, efficiency. (Use the search function for opinions.)

Look at brands, see what fits your budget and your needs. You may find inserts that are smaller than the size you need, but that coordinate with a liner that fit between the insert and your cabinetry to be the right size.

Talk to your installer, be sure they do not cut corners on the size of the ducts, and that they minimize turns in your ducting for optimal suckage and quietness.

Last step:(the one I am on now) pray that the set-up you assembled will be what you need. I really think this was the hardest thing-each part of the decision is so personalized to your situation-the length of your ducts, the style of your cooking.

Good Luck!

thanks jcoxmd! No offense taken on the idiot guide- this is one of the few areas of the remodel where I shied away from getting spun up on becuase its hidden and its a fan in the end- glamour quotient, very low. (I know, I know, I will feel differently the 3rd time the fire dept shows up for my smokey kitchen). Yes the 100 was a typo- I'm clueless on blowers, but not quite that far gone.

Anyway, thanks to your tutorials, I think I ended up with a 40 inch liner for my 42 inch hood with 1200 CFMs. I am getting the 4 burner with grill (grill a recent change, was dead against them, then all the sudden...dont know, somehow started leaning towards them!) so hopefully it will fit the bill. Also my unhelpful GE guy didnt tell me monogram had liners for 42 inch hoods, so I get my 1000 rebate on my 1050 blower and all is right with the world.

I hope.

ADH673 see this thread
http://ths.gardenweb.com/forums/load/appl/msg0711031226925.html

It's up top nine posts so far. Very instructive.

It covers the one big point I left out in my first response: the canopy volume.

Warm air (rising air) displaces other air immediately, and often it will scoot past the opening that supposedly was going to catch it and suck it outdoors. This happens in the blink of an eye. A twentieth of a second.

The need for a (pick a term): funnel / canopy / umbrella shape / hood / is obvious: to hold it while the suction catches up. Warm air has to go somewhere. Going into a hood means it displaces cooler air and gets trapped in the hold for a quarter-second or two before suction takes it outside.

hth

Here is a link that might be useful: puzzled by CFM/cost, perimeter suction, cleaning