I have a water softener and reverse osmosis system. Both are installed in the basement near the furnace. They aren't very intrusive. I also hear that the lowe's/home depot ones do not last long. I had one from HD that lasted 3 years. My current one has a 25 year warranty, and a removeable display head that I can bring in for them to troubleshoot any potential issues, instead of paying for a house call.
For you Florida guys: A "furnace" is a device that burns fuel to keep you warm when it gets cold out.