I'm going with glass tile. It may be about 'done' as a popular option but I've never had it before and am attracted to it. Mine came from Lowes, where there were a number of color options.

It's going to be beautiful!

This is my pick for you, and one of my favorite glass mosaic tiles at the moment. It's mostly grey but has some warmth in it that will echo the warmth in your floor tiles. There is a light grey in this family of tiles if you want to keep things cooler, as well as a brown/blue combo that is just spectacular, if you want to bring in a little splash of color.

Here is a link that might be useful: Mosaic

Hope you do not mind my playing around.

Really pretty tiles EAM44

The onyx tiles are not talking to me with your counter top. They look nice with your floors but not with the counter top - just the wrong shades for me. (I love the tile on its own and it would have been a great choice for our accent tile)

Glazier glass allows you to back paint in any BM or SW color - so lots of flexibility.
Glass tile oasis is another company - they don't customize but has some other color choices and mosaics.

There are a couple of other companies that have color options - I think Ann Sachs was one.

Our local tile shop only had latte, brown, and frosted glass - I think a neat shade of gray - or if there is another color in the counter top - pull that in!

Thanks for the suggestions everyone! My husband and I love the look of the glass mosaic tiles. We haven't decided yet, but that is definitely a front runner. Will post a pic when completed. Thanks again!