CA -
As mentioned no new or old assault weapons, 10 day waiting period for all firearms purchases, must complete safety course paperwork for pistol purchases, pisotls are registered, approved handgun list, no class III
NYS -
Rifles/shotguns easy but pistols require registration and approval by some government authority. Cannot be in NYS with an unregistered pistol unless traveling through without stopping, no AW unless post ban. Magazine capacity limit (AW style ban). No class III either.
NYC -
Must register everything, have everything approved before even thinking about buying a gun. Way too restrictive. NYS carry permits are invalid in NYC, just way too much BS. Everything is pretty much a no, no. Owning a high cap. mag is also evil and a felony.
NJ -
Need to get firearms ID card to own/purchase any firearm. Pistols must be registered and you must get approval from local PD to purchase a pistol, rifles/shotgun purchases registered. Restrictive AW ban but post ban rifles are OK (as far as I know). Damn near impossible to get a CCW permit, magazine capacities limited to 15 rounds, no class III
HI -
Permit to purchase any firearm, registration of all firearms, chief of police regulate permits to purchase, restrictive assault pistol ban, no class III; I don't know of anything else on top of this....
MA -
Restrictive permited purchasing process, State defined classes of fireamrs (A and B) along with your Firearms Identification Card (FID), AW ban (like federal but does not sunset), restrictions on magazines, .gov approved, no machineguns, airguns and BB guns are also regulated, probably more that I don't know about.
CT -
Permit process to purchase a pistol, 2 week waiting period, perminant AW ban, cannot bring in prebans or sell them, restrictive storage requirements
MD -
Perminant AW ban, handgun purchases go through state police, cannot purchase more than 1 handgun or assault weapon in a 30 day period, must complete a safety course to buy a regulated firearm or pistol, registration of AW, approved roster of handguns, MGs are OK, assault pistol restrictions, magazine capacity limited to 20.
IL -
Must get FOID card to do anything related to firearms including purchasing, transportation, purchase of ammunition, etc, no class III. Chicago his full firearm registration and has banned all handguns. Other municipalities have followed. There is no provision for CCW in IL (not aware of any open carry permission either).
DC -
All firearms registered, no new pisols in DC after 1976. Must have gun locked up at home (self defense is not allowed in one's own home). Technically not even permitted to travel through DC with an unregistered firearm even if it is locked up in your trunk with ammo separated.
Most of the listed states have storage requiremnts or trigger lock requirements. Many require that all firearms transfers go through a FFL.
I think that pretty much sums it up. States like KS, NE, and others do not have CCW laws yet. I don't know all the laws but those are the ones I pretty much know. When I graduated college I went looking for jobs and the above mentioned areas pretty much decided where I was going to live.