I have 2 tiered at our lake house and counter height at home. I love each of them in their respective spaces, and I think a lot depends on your layout & how you plan to use the island. Our home island seats four - not all lined up, but 2 stools on each of a short & long end. It is a single top slab -no prep sink/cooktop - and is essentially our everyday eating spot. It's open to a sunroom/seating area so I can chat with anyone sitting there without them being on top of me while I work. At the lake house the bar height helps denote the space between the kitchen & LR in the open floor plan. We entertain casually there and the higher tier works well as a place to put out appetizers and drinks while still allowing the counter height level to continue to be used for food prep. One thing to consider is whether small children will be sitting at the island regularly. Bar height stools can be hard to climb onto and rather high up for toddlers & pre schoolers. My Dad who is in his mid 80's finds my counter height seating easier to manage than bar height. Just some thoughts to consider.

Thanks for all the great feedback! I hadn't thought about using the island as a serving buffet for parties, but I can see how that would be very useful. Also, the point about the comfort of the counter height stools vs. higher ones. My husband is tall, but I'm 5'5" and our son is only 14 months old. So probably lower seating would be more comfortable for us (and the grandparents). Right now we're not entertaining much, since we are busy chasing after the toddler, but pre-baby we entertained a lot and I'm hoping to again, once he gets a little older. I'm trying to plan for that. And I assume that down the road, he'll be doing homework in the kitchen and having friends over after school, etc. We do have a huge table in the diningroom, but that space doubles as our home office, so it's always covered with clutter (2 laptops, mail, paperwork, printing supplies, etc.). It would be nice to have an open expanse of space in the kitchen for actual kitchen projects, but I guess I'm afraid that we'll just fill that space up with clutter, too. ;) For those with the single-level island, how do you light your workspace? We were thinking of installing task lighting under the overhang from the bar to light the counter. Now we'll have to rely solely on pendant lighting, I guess. Is that sufficient? Also, do you have power outlets on the island? If we don't have a vertical surface behind the counter, it seems to limit us in terms of where we can plug in appliances.

There is actually no minimum. You can sit at a stool with the 1-1/2" overhang if you feel like it. It would not be practical or comfortable but there's no law against it. It's a recommendation. And it depends on what you are going to use it for. I don't even like to sit at a counter to eat or drink at a bar or diner, or a high top. I like to sit at a regular height table So if you have a regular height table in the kitchen and this is going to be as a perch where you can kinda sit sideways, or for a snack or a drink, fine, it can be on the shallow side, especially if you don't have a lot of extra room. If this is going to be the only place you eat, or you eat there frequently I would go with the recommendations that Buehl has mentioned. However, you will also need support that is tied into the cabinetry to support the overhang, and decorative brackets that are screwed on to the surface of the cabinet are not adequate. The metal angle irons that I have are required to be attached to the inside surface of a cabinet (which requires extra material) or the inside of a pony wall so the bracket rests on top of the ponywall and is not just attached to the face, or behind a thin layer of paneling. Depending upon these factors, it may make sense for you to go with a technically too shallow overhang depending upon what you actual daily needs are. Not a lot of older kitchens can spare a full 18" inches, or a total of 42" for a peninsula.

When I was designing furniture before I retired, the barstools I designed generally had seat heights of 29", and there would be a foot rail 10" above the floor. All of our furniture was made to order, and so clients could order barstools with whatever seat height they wanted, and some people wanted 27" and some would want 25", but 25" was a low as I remember producing. We also made some with 30" seat heights, but the seats were soft and would compress significantly. The company I worked for is no longer in business, and so this won't help you, but you could find barstools at a custom company and order them with the seat height you want. We had two sets of barstools in Cathedral City - one for the bistro table and one for the bar, which had higher seat heights. I'm not there now, and so I cannot measure the barstools we still have, but we only have outdoor stools - one set is metal and came with the house, and the others are teak, which we had in L.A. I believe that they have 29" seat heights, but that is just a guess.