I'm 5'4" and our island is at counter height and it works fine for me. DH isn't much taller than I at 5'6". Also consider what you are putting in the island. Standard height is better for appliances if you have any....

Part of our island is counter height (36") and then part of it drops down to table height (30"). I'm 5'2" and standard counter height is fine for me to prep on, but the lower part is for rolling things out (need leverage!), making things with the grandkids, and for eating (that's where our chairs are).

If you'll be in the house for a while and you're the primary cook, then by all means get the height you want. I went the opposite direction and did our island 2" higher than standard. I don't roll dough, but for the prep that I do the extra 2" is very noticeable compared to my perimeter counters at standard height.

We have 33 - 34" counters in 3 places in our kitchen (island, stove wall, and baking center). I'm just under 5'4", and my dh and a couple of our sons are 5'10". I love them for baking, prep, etc, and the boys don't have any problems with them. And no one visiting our kitchen even notices we have different counter heights. Our cleanup wall and breakfast center are standard, 36" height, which is fine, and necessary for the dishwasher.

Our bathroom counter is also 36" and I really wish it was 34". That couple inches makes a difference.

I think it is important to put in what suits you best. Shortie like us need the right leverage for baking and the right angle for chopping. Our kitchen has three different height countertops. The island is 32" at the prep/work end and 33" at the eating/table end. (The floor slopes.) The cooktop is 34"- the best height for me to flip skillets and reach the back burners. Cleanup counter is 36". Anyone needing a higher counter for prep can use that, but I've never have tall people looking for a higher counter.

I think it depends not only on height but arm length. I'm 5' 1" but that is because my legs are short - my torso is pretty normal height. My arms are short too so I find the 36" counter height relatively comfortable. We kept the island at 36" partly because we didn't want to lose 2" of storage height under the counter.

For a 34" high island, one also might want to use a less deep prep sink if you will have one there. Ours is 10" deep and I can reach the bottom fine, but two inches lower it would start to require too much bending.

A lower height would have been nice on the range top for me. It's okay at 36" but 34" would ease reaching into deep pots and back burners.

We, too, have a lower island. The butcher block half is at 34" and the granite baking "center" half is at 33". I'm 5'4" and find both heights much better for me for chopping/prep as well as for kneading, rolling and forming dough. DH is 5'11" and he easily works on the butcher block. I would not be as happy with a regular 36" height for these purposes.

Others have brought up good points about height, arm length and the like. When all is said and done, put in what you want and what will make using the kitchen every day best for you.

Here's a thread I started on the same:

Here is a link that might be useful: Lowered Countertops

I'm 6'4" and would love higher counters but std. heights work fine too. You will find selecting chairs easier if you stick with standards and appliances too.
Having said all that, i'd design it for me, if I was you.

Thanks, everyone, I am reassured to go ahead with the lowered counter tops. I hope this is our forever house, which means when I'm old and even shorter, I'll really appreciate them!