time travel is a popular and commonly used concept sometimes overused but not as much as you would expect. The best movies i've seen have not only been entertaining but logical as well. the worst ones i've seen offered little insight as to how it would work.
The back to the future movies did it great they were entertaining and made you think about the consequences of time travel but in a very lighthearted way as well.
The terminator movies follow as well just because of the action and entertainment value alone but they offer little logic in too the concept of time travel since the whole movie takes place after the time travel happened.
I was disappointed with a sound of thunder and timeline. A sound of thunder mainly because it just plain sucked and had several logical flaws in it such as time changing in waves. Timeline was alright though compared to that other pile of junk but it was disappointing to watch I thought that the marines that went with them would not have been such pussies and died so early.
The movie adaptation of the time machine was a good movie by the time it ended but it was kind of dumb in ways. The super genius at the end gives the time machine back to the main character and he can read his mind as well yet he was trick and killed when he could have very easily killed the main character at any time. The logic was ok but left questions as well when he travels back to save his girlfriend he never encounters his past self he should have. his girlfriend dies again but he only tries to save her once with the machine and he should have tried more times. when he goes to the future to find the answer he is told that he built the machine because she died so if she never died it would never exist so he would be unable to go back and save her it makes sense so it puts some decent logic into the movie but not good logic.
whats your opinion on the best and wort time travel movies.