The vault car chase in part 5, simply mind-blowing.
Dom and Hobbs teaming up in part 5. When Dom is giving his big "You can do what you want, and I won't think less of you, but I have to do this" speech, and everyone is looking unsure and full of doubt, then Hobbs steps up with "I'll ride with you Toretto", pretty much everyone in the theater I saw it in broke out in a cheer.
The epic scramble towards the end of the second movie - first the big pickups are sent out to plow the cop cars out of the way, then about a hundred or so cars shoot out of the garage, causing mass confusion.
The battle of East and West at the end of Tokyo Drift — Sean's Mustang (with the engine of Han's Silvia) vs. DK's Fairlady on a mountain DK is apparently master of (it was said that he is the only person capable of going down in one piece.)
Dom bursting out of the cave and plowing into Fenix, with Brian holding him so he can't escape.]