> i don't like renting games(and requiring constant connection to server makes it renting)
You could try the cracked version. I heard that removed this 'feature' from Assassin's Creed, and it is very likely then they will remove it from D3 too.
Of course, chances are that you may not be able to log in from cracked version - and will have to play as a single player game.
Diablo 2 actually had all business logic in the client itself because it needed to support single player and LAN play. They were able to just use the BNetD project to run Diablo 2 compatible battle.net servers with very little D2 specific logic.
A better comparison is probably WoW. Like Diablo 3, all of the business logic is server side and it did take awhile for emulators to pop up.
You could try the cracked version. I heard that removed this 'feature' from Assassin's Creed, and it is very likely then they will remove it from D3 too.
Of course, chances are that you may not be able to log in from cracked version - and will have to play as a single player game.