I had this exact same issue when I started designing my kitchen a few months back. My island will also be 6.5' long, and I ended up drawing the setup in autocad with the dimensions I was interested in. I ended up settling on the configuration in the image I attached. The island is 6.5 long, and the pendants are 14" in width. I think ultimately there's no right answer in a vacuum, depends on the other elements in your kitchen. Our island sits prominently in the middle of the kitchen and is the focal point when you first walk in. Our cabinets are also very simple, done purposefully so we could go a bit more extravagant on the finishing details including islanding lighting, hardware, and faucets. We played around with lights bigger than these and it didn't look right. We also played around with 2 light setups and it felt off to me. Good luck with what you choose!

My island is smaller than yours - a little over 6' x 3' - and I went with three smaller ones. Main reason was function: the sink is in the island and I wanted maximum light on that instead of two lights flanking it. Also, the location of our joists and ceiling ducting dictated that pendants could not be hung perfectly symmetrically, whether we went with two exactly one-third of the way in from each side, or three placed at quarter intervals. Since the island layout is also asymmetrical (big sink flanked by dishwasher on one side and smallish trash pullout on the other), placing three lights slightly asymmetrically mimicked the asymmetry of the island and made the whole feel planned and purposeful. With two, nothing above lined up with what was below. With three, we created the illusion of some symmetry.

Thank you! The pendants are from RH as the poster above mentioned. mommytoc -do you have any pictures of your kitchen? They do make a larger pendant, I've already purchased the three 9", hopefully I'll be able to return 1, or exchange them. I am absolutely going to do a mock up! Great ideas

We are using 3 of the 10" Pottery Barn City Glass pendants over our 9' island. I was also worried about having enough task lighting, so we added a can light over the island sink. Just wanted to add that many use lanterns over the island for an airy look and plenty of light.