Not sure what you consider a small kitchen but mine is only 11x12. The styles and rails on my cabinet are 2-1/4 inches.
Here is an overall shot of my cabinets:

And a closer up shot:

2 1/4'' wide rails and stiles are traditional. The wider rails & stiles have a more modern vibe.

Mine are 2-3/8.

Maria--Below is a thread on this very topic from a couple of weeks ago. Lots of pics and discussion!

Here is a link that might be useful: Thread on shaker stiles and rails

Here is a picture of a kitchen from the Chicago Mart. The stiles on it are 3" on the top and sides and 4" on the bottom. I love it and am modeling my cabinets after this look. The doors were also a full one inch thick. With inset doors, a full 3/4" thickness would work just as well. I think it gives a more farmhouse look. The hardware is really what sets the look too. The hardware on the picture is a little heavy looking to me and more modern. I am going to use bin pulls and thumb latches.

Seems like most people opt for the more narrow/traditional look.
Badgergal, thank you for posting pictures. I've seen your kitchen in other threads, it's gorgeous!
My KD said the sample door I got with the 3 inch rails is the most common style and if I wanted 2 1/4 inch rails it would be a special order (which sounds expensive). That doesn't sound right to me. Should be the other way around.
Breezygirl, thank you for that link. It was very helpful!

Ours are 2 3/16"

My drawer rails are 1.5" and stiles are 2.25". Wouldn't have much room for hardware on top drawers if the rails were the same width as the stiles. Door rails and stiles are both 2.25".

Mine are 2-1/4"

I have 3 inch in my laundry room and they do seem a bit more modern than the smaller but not chunky or clumsy. If you have a lot of narrow doors in your kitchen then the 3 inch may look too thick.

{{!gwi}}

I had a KD telling me the same thing, but it really was a more modern, chunky look than I wanted in my little kitchen. We ended up with a slightly different design, different company, with 2"ish rails and a slight detail on the inside edge to soften it a little. It probably wouldn't be called Shaker anymore due to that, but I love it (being installed currently).

3 1/2 inches here. Curious, my kitchen is not modern.

Wider stiles to me are more vintage looking than modern. Narrow stiles tend to be more contemporary looking IMHO.
Pirula do you have pictures of your kitchen?

I should have said overlay with 3 inch tends to look more modern, but really it all is in how they are combined with other elements. Typically the older kitchens were slimmer or were not shaker style at all .

Mine are 2 3/8 on the doors, but the drawer stiles are 1 1/4, so there is room for hardware.

Nancy

Thank you so much for all your responses! They have been very helpful.

quiltgirl, here are some pictures of our kitchen....

I've been wondering the same thing. Can some of you who responded post pictures of yours?

This blogger chose 3" said it's not as common
http://www.mariakillam.com/2012/05/marias-kitchen-details.html

A few pics of her finished kitchen. Would like to see more of the cabs from different angles without the Xmas decor and photo staging do-dads.
http://www.mariakillam.com/2012/12/marias-christmas-white-kitchen-before-after.html