You know what Mason, I vote for a white kitchen!! I'm not too sure about your climate and how that could impact the white wood cabinets since I'm not an expert in that area, but as a designer, white kitchens communicate one thing to me: timeless. A white kitchen outlives all other trends because it's clean, relatable, fresh and classic. Most importantly, a white kitchen allows you to have options - you can go with different colored appliances, or use accents of color with your countertops or kitchen decor, incorporating your own personal style as well. Since remodeling your kitchen or cabinetry can be a costly project, I recommend making a remodel that can result in long term value. A white kitchen is universally beautiful and allows you to showcase your personal style. This means that you won't be confined to a particular trendy style that will no longer be relevant 10 years from now. Hope this helps but for what it's worth I say go for your dream white kitchen! Because, why not?!

I may not be a pro, but I've been around long enough to tell you that white is not timeless. I've seen many changes and the only thing that is constant is change.
I've seen everything from painted metal, Youngstown kitchens from the fifties, stained wood, or stained cabinets with just the doors painted that were popular in the seventies (the later of which may have been influenced by Peit Mondrain). The first I remember of seeing white cabinets was in the early eighties when the Euro style became popular, where the doors were white laminate with natural horizontal oak trim along the tops of the base cabinet doors & drawers and bottom of upper cabinet doors.

In my opinion, do what you want. If you want white cabinets, get them. If you fear the designer is correct, then get yourself a whole house humidifier. It's not a bad idea to have one for health purposes also. My personal choice is stained wood. To me they give a richer appearance, but not everyone feels that way.

Sorry, I could not find exact photo of the way I remember painted cabinets from the seventies.

The kitchen designer at Lowes is only partially right. Yes Calgary has a very dry climate as compared to say Quebec (where most of these big box stores cabinet suppliers are from). So if you order from say Lowes or Home Depot, etc then yes there is a chance that the doors will shrink as they dry out in our climate. I've personally had this happen on various jobs where my clients want a big box store style cabinet. The doors have shrunk and have shown cracks. I've even had the doors shrink to the point of warping.

Now if you go with a local supplier or custom cabinet builder, you will avoid a lot of this as the materials they are using are already climatized to our dry environment. Then it doesn't matter if you go with a white Shaker style or a more traditional raised panel maple.

As for white being timeless I partially agree with both previous comments. Nothing is timeless. There are always trends. But that being said there are colours and designs that are more "time neutral" than others. White being one of those things.

You do need to do what you like though. Get what you like now and know that it was a choice that you made that made you happy. If in 10-15 yrs you don't like it, well change it then. There are very few things that will have that kind of lasting affect when it comes to style. If you made the choice yourself and you love it, then you will probably still love it for years to come. Everyone changes as the years go by and so does design.