I'm in southern california with very hard water, household of 2, and
possibly one to two new family additions in the next 2-5 years. What
size of a water softener would I need? Also, how do I know what size of
pipes (1/2", 1", or 1-1/2") do I have?

I have narrow down my selection of water softener to the followings:
1. Sears Kenmore 100 or 150A or 200(?Not Listed)
http://www.sears.com/ and type "water softener" in search box
PROS: Popular Brand
CONS: Big; Might Required Complex Installtion; Tedious Salt
Replacement (Monthly basis?)

2. Kinetico 2020c:
http://www.kinetico.com/
PROS: No Electricity Required; Small and Compact
CONS: $$$$$ (Price unknown, but probably very expensive)

3. HardWaterWizard
http://www.alloysafe.com/?Page=../ca....cfm&CatID=337
PROS: Small and Compact; Cheap
CONS: Unknown brand, might be scam???