Pretty kitchen! Lighting is very personal, and I second the ideas to visit a lighting store and see if you can work with a lighting designer. You might consider a linear chandelier that has some length as well as width (I'm using this one, which is 61"L x 30"W, but my island will be longer and narrower than yours; also I have some can lights.) Since your island is almost square, you might be able to get a large light in a round or oval shape, as long as it's not too tall. There are SO many options, and again, visit a showroom (or a few) to see what you like.

Personally I like your big island, but you will need to walk around it to clean it.