All intellectual property would be limited to an absolute maximum of 23 years (a nine year term with up to two seven year extensions which would only apply to corporations[ie. private citizens could copy freely after nine years even if the extension was granted]). Penalties would scale directly to the offender's monetary gain from the infringement (so infringement without monetary gain would carry no penalty at all). Share-alike licenses would be enforced more strictly.
Pornography, blasphemy, and violence in the media would all be made explicitly protected speech.
The constitution would be amended to explicitly ban the development of any sort of "thoughtcrime" laws once technology makes these feasible.
All factors that currently negate consent in some jurisdictions (drunkenness, etc), , would (with exceptions solely for coercion or drugging someone without their consent to said drugs) no longer apply. ("Yes means yes")
All of the FCC's censorship rules would be voided
Universal healthcare for all legitimate (ie no funding for plastic surgery, medically unnecessary abortions, skin bleaching, penis enlargement, or boner pills) medical issues.
Legalization of prostitution
Elimination of corporate personhood
Election reform (both campaign finance reform and also things like elimination of the electoral college, moving election day to either a saturday or a fixed date and making it a national holiday, and moves towards breaking up the two-party system (perhaps a two stage election where an initial open election determines the sole two candidates for the second stage of the election, so in the initial stage people won't be afraid of throwing away their vote and feel less compelled to vote against the candidate they don't want instead of for the one they want))
Reduce the age requirement for congressmen and presidents to around 23.
Remove the clause in the constitution that requires the president to have been born on American soil.
Legalize soft drugs (under restrictions similar to those on booze and cigarettes)
If I had control of the entire world on the other hand and there was therefore nowhere where people and businesses could jump ship to I'd make some much more severe changes including draconian restrictions on business, even shorter intellectual property terms, the immediate invalidation of ALL of the Walt Disney Corporation's intellectual property as punishment for pushing the Mickey Mouse Protection Act through congress, coverage for some forms of plastic surgery under universal healthcare, the conversion of Jerusalem into something similar to Las Vegas but with more and cheaper hookers, the keelhauling of MPAA and RIAA representatives and decision makers, and general moves towards mechanization, globalization, and a post-scarcity post-ethnic society.
EDIT:
Also tort reform.
EDIT:
Also government subsidized bike generators. Save money, save the environment, and lose weight all at once.
EDIT:
Also a government program to develop new GMO supercrops
EDIT:
Depending on results of drug legalization 4-20 and/or 4-19 may be made national holidays