"when they installed the baseboard, there are gaps between the floor and the baseboard. " Out of level or out of flat? It sounds more like out of flat, and depending on how much it might have been simple (just a few shims) or very complex (like ripping out the sub floor and shimming or sistering the joists). You can always hide the variation with shoe mold or quarter round (I think it makes a more finished look with some molding that matches the floor material and finish anyway).

Thanks everyone - so helpful. I will have to think about whether to do a "flat" look like MDBMom or a return into the toe kick like catbuilder or suzannes1 suggested. Hollysprings - I just stood at my counter and while my toes aren't under the toe kick, they are in the about 1" space that the baseboard/shoe combination would take up in front of the cabinet, and since this is a primary workspace I think I need to keep the toe kick. Thanks again for all the pictures, really helped me visualize the options.

Chisue: Thanks for your comments. I am not sure about the lengths that prefinsihed comes in. I need to work that out. Good point if we lay the hardwood across the hall (rather than the length of the hall) it will lnot look chopped up at the bedroom door, closets and living room as that direction would just continue in to these rooms. The other door ways (laundry and bath off the hall) switches to tile. Yes diagonal is more modern. Probably why DH likes it better than I do, as I prefer a more transitional than he does. Amberm: Hope you are enjoying your Ontario visit. I would love to see a photo of your hardwood transitions when you get back to AB (Calgary right?). Thanks for the guidance on joist strucuture if we have plywood (vs the subfloorless days of yore). Our old subfloor is only unlevel in a few points (a few sags). A 1/4 inch would make it taller than the new subfloor. It seems the framers lowered the new floor so it would be on the same plane as the old subfloor. It may be that DH can use 1/8 inch plywood in a few low points instead of the messy leveling compound. Thanks for that suggestion. Do you happen to have a vote on best hardwood direction in our floor plan? Carol

Whats standard? Might depend on where you live. :-) In Arizona, my tract builder routinely used grout to seal the gap between the tile and the baseboard (they used *nothing* between the carpet and baseboard). I never had any complaints with the grout, even after our house flooded. In Texas, my tract builder routinely used caulk to seal the gap between the tile and the baseboard (again, nothing was used between carpet and baseboard). I, personally, dislike the aesthetics of white caulk (to match white baseboards) running along the bottom of every wall -- it has always reminded me of a bathroom. When I viewed the model homes, it felt like I was walking through a ginormous bathroom. :-/ As an experiment, my husband beautifully installed beadboard and beefy baseboards in our pantry, and when he sealed the baseboard/floor, he used a very thin line of caulk that matched the *grout*. It looks a million times better. I remember asking a similar question here on GardenWeb, a few years back, when my current home was being built... And I think it was a member named "worthy" who mentioned using caulk as a barrier for insects. That pretty much sold me on the idea, since we have fire ants here (had over 300 scorpions in our house in AZ, the first year we lived there; I'll take fire ants any time!). Unfortunately, you'd have to caulk/grout EVERY baseboard, which tract builders won't typically do if you have carpet anywhere. Based on your photos (except the first one -- that's really sloppy), I love that the builder seems to have tiled *to the wall* and then put the baseboards on. My builder -- sigh -- tiled roughly 1/4 of an inch away from where they anticipated the baseboard would be (I actually have 1/2" of caulked space between tile and baseboard in a hallway), so I have a ton of horizontal caulk lines all over the place that trap dirt and shrink up. Scrubbing caulk with baby wipes is fun. :-/