Soft water
I believe most people don't condition their water because they don't know what they are missing. Until one has lived with softened water they won't understand the benefits. They far outweigh the drawbacks, IMO. Everything is much better with softened water. Appliances are much happier, clothes and dishes are much cleaner (especially with no phosphates in the detergents anymore), and hard water film on bathroom fixtures and in toilet tanks is practically non-existent.
Some claim that softened water is bad for ones health because the minerals are good for bone strength and the extra sodium is bad for older people's water retention and blood pressure. I tend to disagree with that premise. The amount of sodium in softened water compaired to what is hidden in ones food is extremely minor. As far as the minerals go, they can easily be replaced with a good diet and/or supplements.
I just filled our salt tank up yesterday with 240 lbs. of salt and that will last at least a year and it was only $30.00. Our toilets are from the '60's (3 of them) and use around 4 or 5 gal. per flush, a bathtub and shower with no restrictors on the shower heads, a Maytag A806 set, and two dishwashers (one K/A KDS-20 and one K/A made in 2000). We're conservative with our water usage. We only flush the toilets when necessary (if it's yellow let it mellow - that old California saying), run the washer and dishwashers when full and showers are quick because we don't have to stand around waiting for the proper amount of water to come out. It all works perfectly and I wouldn't have it any other way.
There is one minor drawback to softened water. One has to check the anode rod in the water heater frequently or get an electrically powered anode rod from waterheaterrescue.com. Softened water tends to shorten the life of a w/h without one. Once I got the w/h problem fixed everything was perfect. Of course, if one lives in an apartment, a water softener is usually out of the question.
In summary - softened water is fantastic. On a side note. Be careful in the tub, especially when the soap and shampoo come out. The bottom of that tub will get very slick. I envy people who have naturally soft water.