Would you consider running your filtered water into your refrigerator? I have a reverse osmosis system under my sink and have a tap there and also run water (under the floor) across the kitchen to the refrigerator for cold water and ice.

There are many water filters on the market that are installed under the counter. But if you really want a good one, I agree with the above, a reverse osmosis system is the best option to provide the best quality water. It is tapped into the cold water line, so the water is cold, however, once it sits in the holding tank for some time, it will warm up, but it still cool to cold. Not as cold as running the water from the tap for a few minutes, but still.

Here is a link that might be useful: Aquasafe Systems