Also, read through this briefly
http://www.nrdc.org/water/drinking/uscities.asp
I haven't read everything on the site, and don't necessarily agree with the whole political slant, but it makes an interesting point:
The pipes that were laid for the water usage may be
old (I read an article once about how the pipes were laid in the 60s and haven't been updated since).
So, even if the water tests clean at the main site, it may still be contaminated after it comes out of the tap.
That, and the fact that the water plants don't test for things like hormones (excreted in large amounts since the birth of the pill), and don't have any practical way to remove them, I choose RO.
I guess what would be best is RO with an alkaline attachment just before the faucet?