[ersgklbg] Laws which are importantly different state to state

Enumerate laws which are different between states.  Crowdsourcing might be useful.  We would also like some measure of how "important" the difference is.  In particular, which are laws for which the social experiment of two approaches has gone on long enough to pick whose law is better?  Such laws should be normalized.

RomneyCare
Marijuana
Gay marriage
Assisted suicide
Age of consent (including Romeo and Juliet)
SLAPP
Non-compete clauses in employment contracts
State sales tax
State income tax
State property tax
State corporate income tax