It is not only a "good idea," it is the best way to do it. Do a search on range hoods here and you will see that there is a general rule of thumb to have a hood that is the next size wider than the width of the stove. This collects more steam and etc. from the stove. When the hood is the same width as the stove, and not confined by cabinets, some of the vapor will curl out beyond the hood. A wider hood diminishes that. So, 36" hood for a 30" range is recommended. (As you have a 42-inch space, you could go that wide, if you wanted. A more powerful hood can generally run at lower speeds and thus be more quiet. OTOH, a 42" hood is going to be a lot more expensive.) There have been a lot of postings on this subject. Do a search and you will find numbers of redcent in-depth discussions One of the most helpful and knowledgeable GWers on this subject is Kaseki. Something to bear in mind, though, is the CFM rating. Some cities and towns have adopted codes that require make-up air (MUA) for hoods that pull over a certain amount of CFM. Codes vary. Some posters report that 400 CFM is the point where MUA is required, others have 600 CFM. MUA can be a good idea idea even apart from code requirements because it prevents CO backdrafting from elsewhere in a tightly sealed house (say, from a gas water heater or a furnace). Search on MUA here to get more information.

We entertain a lot and cook every night. When we remodeled we replaced the 30" cooktop and double wall oven with a 30" dual fuel range and 30" 240V Advantium wall oven. You will have to learn sequencing with the Advatium for multiple dishes, especially if you are going to use the microwave. The oven needs to cool down some before using the MW. We got a great deal on a GE Monogram Pro DF range and all of them are working perfectly.

Funny, your range/hood set up is pretty much EXACTLY what mine (in the works) is to be. Although I don't have G shaped kitchen...I have a G with a gap in it. My 36 inch range will be on one of the short legs, with 9 inches on either side plus the 24" of the "corner" counter on one side. And I've ordered a 42" hood. ANd no upper cabs on either side of the hood. I plan to make my tiled backsplash run at 18"" (under cabinet height) from the corner to the range, then go up the full height to the hood, then back down for the last 9" stretch of counter. It seems to me that it would look better to have the behind-the-range backsplash align with the size of the range, than with the hood and those "strips" on either side of the range backsplash will simply blend in with the painted wall to the left and right of the hood. I'm interested to know if others have a different opinon though...preferably before I get to the tile work!

I don't think you will notice after a while. Mine is off by about 1" on the left, because the *&^&%$ range hood is a full inch less wide than the rangetop (I swear I bought a 48" range hood, not 47"!). But then again, we are DIY so I wasn't about to make my poor DH uninstall then reinstall all of the lower cabinets after it took him a full day in the first place; if we were paying someone for it, it might be a different story. If you choose to keep it, just make sure you don't do a stacked tile BS - you would probably definitely notice it then. Example of what not to do: http://www.peeltile.com/img/media/backsplash/layout.jpg