I voted manual, just because it's a fun bit of realism, but i would like to choose which transmission is in the cars. Cause automatic is convenient, but sometimes that added sense of control makes it really fun.
automatic cars (whether virtual or real) are stupid and are the main cause for why the vast majority of drivers suck. It takes no skill to drive, and consequently requires a lot less attention to be paid by the driver, which isn't a good thing.
Also (this is just from personal experience) it seemed like the cars in GTA4 only had like 2 gears at maximum, and it always felt like the torque band of the sports cars was way off... I think adding manual gear boxes to the game would alleviate this.
There is nothing in the bible that says Jesus wasnt a Veloci-Raptor Raw dogging the internet (and your gf) since '93