Those fucking remote control planes? Stupid. Few things annoy me more than crappy little mini-games that make no sense, are insanely difficult and completely ruin the flow of the main game. See also the stupid fucking asteroid shooting thing in the middle of Dead Space.
Pretty sure the remote control plane mission wasn't neccesary to the main story. That mission did suck a ton of dick though.
3, San Andreas and Vice City were the shit. 4 not so much; I got so bored I downloaded a saved game file. If 5 has a destroyable environment like the battlefield games have been doing, it will be even more fun to lock people into rooms and throw in the molotov's.
I read somewhere that there is a strong possibility you'll be able to take the role of several different people.
Either the remotes or the one where you had to fly through rings were a part of the main story. I could never finish either.
Vice City was my favorite, but usually I only play the main missions and then by the time I finish I get bored. I'll probably wait for the PC release unless it's really that good.
I've pretty much stopped playing video games. Just don't have the time anymore. I would make an exception for this, though.