Costco.com has a nice double filter setup that comes with it's own high quality faucet.
The set up is only 90 dollars, tells you when the two filters need changing out (2000 gal).
Set up in your kitchen, you would have a tap that delivers pure water for cooking, coffee making , and drinking water. Also for 140.00, they have a a five stage reverse Osmosis system with it's own water tap . This unit comes with a 3 gallon tank so it much larger and would take up most of the space under the sink.
Just some food for thought............or drink for thought.........or whatever.
http://www.costco.com/
Do a search under " Watts water"