I'm in the video game business (among other things...), so I will tell of my experiences with GTA3.
I bought it a few days after it was released, and can honestly say, that is probably the second best game (if not the best) game on the PS2 (the new Metal Gear being the best, but then again, I am partial! [:D]).
Although not because of the excess violence and vulgarity, but because the sheer scope of the game. Imagine being in an entire virtual city with the ability to do ANYTHING you want.
You like the looks of that sports car over there? Just walk up and jack it!
Want to take your M-16 on top of police headquarters and lay waste to hordes of LEO'S, no problem!
You can even pick up a streetwalker if you are so inclined.
I severely doubt this game will go out of print anytime soon though, that is an unsubstantiated rumor. Nevertheless, do yourself a favor and pick a copy up whil there still is a First Amendment still on the books.