I think glass tiles are gorgeous and was actually going to use them for my kitchen, until my tile guy talked me out of them. After the tiles were installed and grouted, I was happy that he did because I can see what he meant when he said he didn't like the effect when both the tile and the countertop were highly reflective. He preferred to use a matte or unpolished stone tile with a polished granite, and a glass or polished tile with a honed granite or marble countertop. Much like Angie likes to mix polished with a bit of RATE, he thought that the contrast made the final result more interesting.
I also was seriously thinking of Ramya's idea of running my wall tile all the way to the ceiling because that makes such perfect sense in a kitchen. I've done that in all of our bathrooms and love how easy it is to clean everything. I finally decided against it in the kitchen mainly because we may sell our house in a year or two and I'm not sure our target market loves tile as much as I do. That was another reason for using the subway tiles; they were much cheaper.
ETA: If you are thinking of using a colored grout, I'd definitely try to find a BIG sample board of the combination. My friend just remodelled her kitchen and chose a bluish grout to set off her white tiles and match her blue granite counters. She hated the final effect so much, so she ended up having it ripped out, much to her husband's dismay since her tiles were fairly expensive. But she just couldn't stand the look.
