In my personal opinion, it haves to be Finland! The gta iv web had clues of it on the traveling site. It says... ''Finland, jackpot to live there? If you love drinking alot of alcohol, hear insults from other drunken people and get robbed on end of the day... You will love Finland!'' And Finland haves really huge crime rates, so it is one possibility. And it would be perfect place for gta to be set in! So, this is my personal opinion... And there also is 3 pedestrians in gta iv that speak finnish! And proofs go on, gta iv had big destroyed billboard with poster under it with some letters missing etc, but with little time and trying to see it more clearly it had Huge V on it but before that there was reading something that was took out, and then there was flag of Finland and under the flag there was reading. ''Suomi, maailman suurimmat rikostilastot!'' That means in english. ''Finland, the highest crime rates!'' So it haves to be in Finland! All these facts point to it!