Im not a fan of modern GTA games. I played a lot original GTA and GTA2. I played GTA3 on PC for about 5-7 hours, GTA4 on X360 for 3 hours and GTA5 on PS4 for 3-4 hours. One day I will try to play more GTA5, but I never wanted to get back to GTA4 after several hours of play. So GTA4 is the worst GTA game I have ever touched. LOL.

Grand Theft Auto: Chinatown Wars

Haven't played I or II, so my answer is IV. Such a borefest. I don't know how that damn game has a Metascore of 98.

Deary me this sites user base must be younger that I thought or didn't game on the Psone at all, I mean GTA:London has to clearly be the worst GTA, not only did it have all of the gameplay and game engine of the first GTA title (as it was a mission pack at first and later released as a standalone game) but also on the PSone you had to change out the disk to load up GTA:Londons stages each time you wanted to load a new stage, it was torture to get to play it, when playing it it was just a cheap addon cashin on the moderate success of the first title, honestly if you think GTAIV is the worst of the series and proves metacritic is bad then dig out a PSone and have a play of GTA:London, you'll be longing for Roman to ring you up and ask you to come bowling with him.... even if it is after the final mission and you made the choice to save the girl, because yeah he is so determined to play bowling he can ring you from beyond the grave for a quick game.

GTAIV: The Thread

I have played most GTA and I like them all, so I'm not sure. I'd say either the originals (though 2 is very good still), or GTA III, as it is the one that was made earlier and doesn't feature much content in comparison (and still, its driving mechanics are much better than both GTA IV and V, not to mention car deformation is much better than the later).

On a side note, I'm not sure why people dislike IV so much. It was a much more grounded story, and the controls were hard to master, but I appreciated the former and you could still cause chaos and be crazy if you wanted to. Sure, customization took a step back and no parachutes on helicopters was a big mistake, but nothing like driving though Liberty City, really. As someone who didn't enjoy San Andreas that much, it was very cool, and impressive back when it first released. You could argue it got old fast, but at that point there wasn't simply anything of a similar scope on the HD machines. 

I'm going to guess a lot of people on here were not fans of being asked to come bowling? :D

Seems a small bit bandwagony to me though I mean objectively to put GTA1/2/London above any of the later games is very strange, you could say that GTA4 had a weak story... but in comparison to a story given to you buy a row of phones in a single paragraph of text? Could just be a case that people didn't play GTA1/2 maybe?

Obviously, comparing a game with massive age difference is never easy. I enjoyed GTA1 and GTA2 a lot, more so than any other later GTA game, it was just mindless fun I had a blast with them and once GTA got serious they lost me. GTA IV is a prime example of a game that wants to be too much and doesnt pull it off, instant turn off for me (96% on metacritic, I have no clue how that happend). I havnt even tried GTA V because of it, I will some day though.