The thread I linked below (in which Buehl quoted Sharb's pantry shelf spacing) helped me tremendously with figuring out the distance between my shelves. I had to adjust for things like placement of the electrical outlets, etc., but it was a very good and helpful start.

Here is another good pantry thread:
http://ths.gardenweb.com/forums/load/decor/msg1110433025538.html

In my pantry, starting from the floor, the spacing between shelves is 19" (floor to shelf), 15", 14", 10", 10", 14", and then 21+" to the ceiling. Photos of my pantry:

Here is a link that might be useful: pantry thread with SharB's distance-betw-shelves measurements

Shelving spacing depends on what you want to store in the pantry. Here is how mine worked out:

bottom shelf -- high enough to stack two cases of long neck beers underneath (as that is what goes on the floor)

next shelf up -- high enough to hold stand mixer, food processor and blender (fully assembled so as to not waste foot print space)

top shelf -- low enough to hold 20qt stock pot and rolls of 12 pack of paper towels

intermediate shelves -- three shelves spaced evenly between top shelf and one up from bottom

The upshot is that I have a few shelves spaced for tall items and the remaining shelves spaced for typical stuff. You will want to make sure that the smallest spacing is high enough to accommodate two stacked cans.

Allow some space for a flat-folding step stool so that you can reach stuff on the top shelf.

FWIW, prior to its remodel, my pantry was not functional. The aforementioned stand mixer was on the floor! I hated it so much that I wanted to get rid of it. Now I am very happy with it.

Best of luck.

Our floor-to-ceiling pantry (not a walk-in) was built with the same adjustable shelves as our cabinets -- those lines of holes at front and back on both sides that those little shelf thingys go into to hold the shelves up.

I've been fiddling with the shelf adjustment ever since we moved back into the kitchen and last night I decided I'd finally gotten it right. I'm glad I had shelves that I could adjust though; I'm not sure I could have figured it out beforehand (or at least I didn't think to before I moved all the stuff out of the pantry!!).

Maybe I should've said why we chose those distances for our pantry?

The 19" from the floor was to fit those wheeled bins for my bulk storage.

My grain mill, gallon sized containers/jugs, cereal boxes, and paper towels can all stand in the 14 and 15" spaces.

10" is about perfect for stacking 2 standard sized cans (you can see in my photo) and for most condiment and salad dressing bottles...with just a little space to spare so they're not too tight to maneuver.