I think the issue is your wall color. The space looks very nice. Trying to darken the travertine is not the way to go. Think about darkening the walls to provide contrast with the cabinets, perhap to a gray shade from the new granite to tie in with the black granite, and consider an update to the lighting to pendants over the island.

I agree with Barbie about doing some type of painting on the
island. Not sure about the black color though, unless you were to rub or wipe
off enough to allow for the under color to come through. This will help tie the
island and main cabinetry together; but allow for the island to stand out as a
feature in the kitchen. I may eve
look at changing out the hardware so that it blends and not stand. Allow the island to do that.

I think you've done a great job. The only change I'd make is to paint the island not black, but dark gray. Find some gray in your new granite and use that as a guide. I'd recommend painting your walls above the window a gray, but I see it extends into he family room. Add some stools with a wrought iron base, and darker (leather?) cushions on it. I'd also get a different rug by the sink. Try a chef's mat in a solid color, or something less busy. Let your new granite and backsplash have focus in your kitchen. Not sure if it's in your plans, cut consider adding pendants over your island too.

take out the decorative panels in the ceiling fixture. and go more simple let that blend away.

also light and bright is not a bad thing. if you look to your nook area its much too dark now. consider lightening up that space. the bookcase seems large. maybe paint it the color of the cabinets?

If staining the island is an option, I think a warm, medium wood tone would tie everything together nicely by pulling color from the backsplash and also complimenting the granite and the floor tile. The easier solution would probably be to paint the island something dark like espresso, charcoal or black. Heres are some quickie mockups to help you visualize it:

I think you need stools that are the same dark colour as your countertops . That should balance things out.

I love that the you chose a different color granite for the island in your re-do, now you need to finish that thought! Instead of part of it matching the surrounding cabinets, make it stand out and be more of a separate furniture piece. Since the surrounding cabinets are light with a dark top... I'd do the opposite feel on the island... you have a lighter top, so the bottom, cabinet part, should be painted dark black.

Then once you have the dark island cabinet, you could have light colored stools to pull that light color from the surrounding cabinets over to the center.

My former house is a great example... only reverse... my surrounding cabinets were dark with lightish tops, so the island was light cabinet with dark top. Here you can barely see the dark cabinets, but it gives you an idea. (This takes you to all the posts I've written about our former kitchen, some of them show the surrounding cabinets better)

I've already got my contractor coming tomorrow morning to take out the light box and install 2 lantern pendants above the island, as well as recessed lights, and molding detail to the island base. I think will help quite a bit. I just wanted to be able to tell him what color to paint it.

I agree that the giant brown entertainment center is dark, and I'll look into painting or replacing it in the future. I like the idea of new hardware...the dark knobs and pulls are accentuating the dark granite. I'd like to avoid painting the cabinets...there are just so many! There's another whole set on the other side of the island. Thanks so much for all the input. If you have any other ideas, just let me know. I'll post updated pics once the pendants go in.

I think the knobs and pulls should be something sleeker and less ornate. There is so much business going on with the granite.

I agree with panting the base of the island a slate grey

The runner is dated. Try something more current, like a subtle stripe or solid .

Basically you have too much business going on -- with 2 granites, a tile backsplash, tile flooring, patterned rug, etc. Its kind of hodge podge which is making you sick of looking at it I think. I would pull everything out and off the counters. slowly and gradually add back in what you really need in terms of the accessories and items on the counter, windows, etc.

Could you pull a faint grey tone from the floor to use as wall color? That coordinates with a darker slate gray for island base?

Id also consider doing a off white subway tile backsplash and ditching what you have there.